This PDF file contains the front matter associated with SPIE Contract Proceedings Volume 7146, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Topological spatial relation between spatial objects is a very important topic for spatial analysis, query and reasoning in Geographic Information Science (GIS). In this paper, an algebraic method using constrained Delaunay triangulation (CDT) for topological spatial relation is presented. In the part of foundational theory, (i) prove CDT is simplicial complex in R². (ii) import chain structure in CDT and prove including & approximating theorem and reduced including & approximating theorem, and are used for estimating left, middle and right side properties of triangle. (iii) define the region in CDT and establish region algebra (RA), which use the set of region as computational space and use the intersection operator as a binary operation. (iv) describe basic forms of node and chain which are contained in a set of triangles. In the part of spatial relation calculation, (i) describe spatial object as three entries, i.e. exterior, boundary and interior, with left, middle and right of triangle and their combination. (ii) establish the topological spatial relation calculation model-region nine intersection model (R9IM), which is used the intersection operation and the form operation as basic operations. (iii) calculate thirty-three spatial relations of simple objects with R9IM in the practice application of topological examination.

To improve the access efficiency of multidimensional spatial database, this study proposes a new index structure named Space Hypercube Grid Tree (SHG-Tree). By avoiding the problems of node split and recombination, SHG-Tree can efficiently support the common operations over spatial database containing objects with dynamic region. The main contributions of this paper include: (1) Proposes SHG-Tree of n-dimensional space with a hierarchical tree structure. It reflects the region overlapping relationship of hypercube grid units with different granularity. (2) Proposes the linearization methods to present the bounding rectangle of object as a union of variant granularity hypercube grids. (3) Gives operations of SHG-Tree. Experiments result shows the size of SHG-Tree is small enough to remain in main memory even to very large spatial database by applying proper linearization strategy and the queries on SHG-Tree are less than ten milliseconds to ensure the real-time of query.

Our city has owned the integrated pipeline network management system with ArcGIS Engine 9.1 as the bottom development platform and with Oracle9i as basic database for storaging data. In this system, ArcGIS SDE9.1 is applied as the spatial data engine, and the system was a synthetic management software developed with Visual Studio visualization procedures development tools. As the pipeline update function of the system has the phenomenon of slower update and even sometimes the data lost, to ensure the underground pipeline data can real-time be updated conveniently and frequently, and the actuality and integrity of the underground pipeline data, we have increased a new update module in the system developed and researched by ourselves. The module has the powerful data update function, and can realize the function of inputting and outputting and rapid update volume of data. The new developed module adopts Visual Studio visualization procedures development tools, and uses access as the basic database to storage data. We can edit the graphics in AutoCAD software, and realize the database update using link between the graphics and the system. Practice shows that the update module has good compatibility with the original system, reliable and high update efficient of the database.

Simply speaking, updates propagation is to use updates from one newly-updated database (called Master Database, MDB) to revise, improve and correct the content of the other database (Called Client Database, CDB) for ensuring that CDB also has a current representation of the terrain. Currently, updates propagation between spatial databases is usually a complex and time-taking process because of the multi-level potential heterogeneities between them and the special requirement of keeping the updated CDB autonomous, complete, correct, and consistent as much as before. To simplify and improve the propagation of updates, a detailed classification of the possible heterogeneities between MDB and CDB is introduced and their influences on updates propagation are also analyzed. Based on these analyses, an appraoch based on schema matching is proposed to effectively implement updates propagation. The automated solutions to operations involved in this approach are discussed in detail, such as schema matching, entity identification, updates extraction, and updates integration.

The Spatial Decision Support System (SDSS), as an emerging field of science and technology, is combined by Geographic Information System (GIS) and decision support system (DSS). Nowadays, more and more attentions have been paid to the technology of SDSS, and the construction of geographic database in SDSS has been a hot-spot for many years. One of the commonly used methods in geographical data management is directly entry spatial and attributes information into the relational database (generally used the Oracle relational database). Metadata plays an important role in process of building and in spatial data management. A case study is introduced. The Beijing Rural Resource Management Geographical Information System (BJRMGIS) is designed for the Beijing Agricultural Research Center, aiming for rural spatial decision support to facilitate its analysis operations. The paper mainly contains two parts from the viewpoint of database, that is, the design of database metadata table and the function of database maintenance. (1) The frame of metadata. According to report of needs analysis, the data in BJRMGIS are classified into four categories: fundamental data, remotely sensed image data, statistical data and multimedia data. Moreover, the map is a special form of data. (2) The database maintenance functions include three modules, that is, user management, database import and database management. This paper put forward the metadata-based database management decision support system model, and process from the practical problems to solve the applications. Also, the construction provides a reference for designing of other similar SDSS systems.

In recent years, the way to manage massive geospatial information of a global scale by Discrete Global Grid Systems (DGGSs) has attracted great attention. In this paper, a new geospatial data index structure is proposed. Firstly, planar multi-resolution hexagon grids are projected to spheres by Snyder Equal-area Polyhedral Projection to construct grid systems. Then, the spatial relationships between spherical hexagon grids are converted into spherical triangle quad-tree by quaternary groups of boundary vertexes. Additionally, extended Quarternary Triangular Mesh (QTM) encoding scheme is utilized in three-axis discrete grid coordinate systems to facilitate the transformation between geographic coordinates and cell address codes. Finally, cell analyzing and searching algorithm are proposed. Experimental results show that the index structure proposed in this paper can operate cell address codes directly and efficiently.

Description and differentiation of topological relations are based on the changes of topological properties of spatial objects sets and their components before and after their intersection. There were many researches about special topological relations between two simple spatial objects, but the researches on topological relations of the spatial objects with a hole are relatively fewer. This paper uses the description frame of two spatial objects with holes, which is put forward by Egenhofer etc. Based on the 4ID, this paper put forward a new extended model which can describe special topological relations between the spatial objects with a hole. At the same time, the paper detrude 23 kinds of topological relations between a simple spatial object and a spatial object with a hole and 57 kinds of topological relations between two spatial objects which only with a hole.

Spatial relation between spatial objects is a very important topic for spatial reasoning, query and analysis in global GIS. However, the most popular models in current use, which are based on the 2D Euclidean space (such as raster), exist some fundamental deficiency in theory for spatial relation reasoning in the spherical digital space (SDS). In this paper, a reasoning method of spatial relations in the SDS based on manifold is approached, in which: (1) the topological definitions, properties, and descriptions of spatial objects in SDS are presented; (2) appropriate operators from set operators (i.e. intersection, difference, difference by, symmetric difference, etc.) are utilized to distinguish the spatial relations between neighboring spatial objects; and (3) the value of the Euler number of symmetric difference is used for the detailed computational results of set operations; In this method, the 8 types basic topological relations between spatial objects in SDS can be distinguished accurately and easily from simple to detailed level for different requirements.

Geospatial information contains not only spatial information and attribute information, but also the information related with spatial information evolvement. As the development of the instruments and technology to acquire geospatial information, more and more geographical information contains spatial-temporal information, as a result, temporal-GIS(Temporal-Geographic Information System, TGIS for short) comes into being. Temporal-GIS could analyze and solve the spatial evolvement characteristics in geographical phenomenon, and reproduce the spatial-temporal scene of real world. This project is focusing on the dynamic visualization of geospatial data based on temporal-GIS, designing the interpreter arithmetic for geospatial polygon dynamic display, building dynamic display model based on temporal-GIS, subsequently, the model is used to analysis and solve the dynamic evolution characteristics of geographic phenomenon, reproduce the real-world temporal -spatial scenes, predict the developing trend of geo-data with the visualization methods.

To solve the problems of massive, multi-source provincial image data management, storage, retrieval, and so on, ArcSDE spatial data engine architecture and data model are used to establish a provincial DOM database by combining Oracle 10g database management system. The establishment of the database of remote sensing images successfully solve some specific problems of the block image data processing, image pyramid building, data compression, etc. Meanwhile, the grid index structure and the method of retrieval based on contents are adopted. It has been proved by practice that the disposal of the images by level and block can store the images in a fast and efficient way. The combination of grid index accelerates the retrieval of the images, and the DOM data can be effectively organized, security storage and effectively used.

It has been acclaimed that the future vision for GIS data sharing might look like this: each of small counties or towns hosts its own online GIS; and each uses software and a data model selected to best meet its own needs. This paper gives a model based on Oracle Spatial, within a local government or enterprise the spatial data is in centralized storage, and with metadata interoperability, which enables the organizations to use the proper tool for the job while eliminating complicated data transfers and duplications throughout the enterprise or different departments. The MapInfo and ArcGIS software have been made to work together under the same oracle spatial database use trigger and storage process. On another hand, with the situation of between the departments or enterprises, a three-tier structure solution is given: spatial data server, application server and application client. The application server is a mediation system, this model uses oracle application server as the mediation system, and through the application server the application client sends WMS or WFS request and get the map server for background application. The three-tier structure model exposes a GIS portal which is an online GIS for external applications. Any client can request the server if it accords with WMS or WFS specification.

The world of today heavily relies on spatial data to manage the natural and built environments, also to construct virtual geographic environments (VGEs). After analyzed the characteristics of multi-sourced heterogeneous spatial data in VGEs, a Data Representation Model oriented to VGEs (XGE-DRM) was designed in this paper. The XGE-DRM provides not only a clear description of the data, but also defines the relationships among the data, it is critical for users to interpret data correctly. XGE-DRM provides a common data model to define a data representation structure for traditional data and spatial data. Using it, users can customize their geographic data to correctly interpret other data. Then the processes and framework of multi-sourced heterogeneous spatial data integration were proposed, and the spatial data parsing was discussed. Lastly, the platform system of multi-sourced heterogeneous spatial data integration was designed and developed under the VS.NET2005 development environment combined with XML technology, and it can solve the bottleneck problems arise in geographic information resources which under the heterogeneous environment. Some experiments were designed and discussed, by those experiments; it had shown that the platform we developed can integrate multi-sourced heterogeneous spatial data effectively and were works better than other similar platform systems.

This paper first defines the concept of GIS-based model(GBM) metadata and analyzes its hierarchy. The second section gives the contents of GBM declarative metadata and services metadata. Then this paper defines the primary mode of GBM metadata based on XML Schema. Finally, this paper discusses the flows of development and application for GBM metadata. This paper improves the GBM attributes information management, which can advance GBM management efficiency and integration ability.

On the basis of the equilateral octahedron in the sphere, the global is recursively subdivided. With level of subdivision increasing, subdivision speed will descend markedly. So for the deeper hierarchy of subdivision, local subdivision is chosen. After the sphere is divided, to display the proper area, the correct cells should be found. So when the specific region is showed, its central cell needs to be as initial search cell to find grid cells within a certain range, and then show. Grid cells after subdivided can not achieve the ideal that the cells have the equal area and the equal shape, which affects the effect of display and the accuracy of search. Through the analysis of cell distortion, it is known that the basic attributes of cells distribute according to a certain law. With level of subdivision increasing, the changes tend to be stable which ensures the reliability of the deeper levels subdivision.

With the broadening and deepening of GIS applications, the GIS system is beginning to process a much larger amount of spatial data. Further analysis and processing of spatial data depend on data quality to a great extent, i.e. the accuracy, integrity and coherence of the data. Different methods have been developed for the purpose of controlling data quality. In this paper, a novel solution is proposed, which is a workflow-based system design for the online inspection of spatial data combined with the role-task based access control model and the versioning function of ArcSDE on a database. The design is charactered by precise workflow modeling of the online inspection of spatial data. There are two significant advantages about this design: a) A more secure access control mechanism in GIS workflow; b) A more effective solution to support long transactions of GIS workflow. This workflow-based system design has been successfully used in the active fault seismic data which have been collected from more than twenty cities in China and include different disciplines. It is charactered by stronger security and easier maintenance. Moreover, it can also be used for other kinds of online inspection of spatial data with its universal applicability.

This paper reviews the progress of the research on spatial data interoperability and several methods currently used to achieving spatial data interoperability, puts the emphasis on analyzing the advantages, as well as the handicaps and existing conditions of interoperability based on shared database and the discrepancy of data models specific to different GIS, which is a main obstacle to spatial data interoperability, and brings forward two methods for achieving spatial data interoperability based on shared spatial database: one is realizing spatial data interoperability among different clients by using the same set of data model in database, the other is interoperability among clients through objects translation in a shared database. The paper also makes a comparison between these two methods in feasibility and difficulty of carrying out. Based on the analysis, this paper makes an experiment with Oracle Spatial in a local network using the second method, the emphasis of the experiment is put on the interoperability of oriented point objects and text, or annotation objects, as the two types of objects have no standard data model in Oracle Spatial and data models brought forward by different GIS vendor used to describe these two types of objects are specific to their GIS software. Two GIS software, MapInfo and Geomedia, are used as client in the experiment. The experiment shows that this method to achieve spatial data interoperability is practical and could be used inside an organization by employees in different departments, who are familiar with different software in their work, to obtain data sharing and interoperability. This method can also lower data redundancy and improve work efficiency.

Temporality is the distinct attribute of cadastral information. It is very important to scientifically and efficiently manage three kinds of data that exist in the Cadastral Information System, such as spatial data, temporal data and attributive data.Based on the research of TGIS and the advantages of existing spatio-temporal database model. This paper proposes a design of a spatio-temporal cadastral database which is divided into historical database and alterative database. This design fulfills the requirements for management of cadastral data and reduces data redundance and enhances the efficiency of database.

With the enrichment of earth observing measures, the interesting field of photogrammetry and remote sensing monitoring has expanded gradually to the whole world, traditional planar data structure no longer satisfies the globaloriented application of geo-spatial data. Breaking through the constraints of planes, managing and utilizing remote sensing spatial data in the real earth mode have now become an inevitable trend. Discrete Global Grid System (DGGS) provides new ideas for the constructing of new spatial data models. Based on the frame of DGGS, this paper designs a new hexagonal hierarchical structure of remote sensing data that has the attribute of geographical location. Compared with the traditional image rectangular quadtree structure, this structure is more applicable to the management and arrangement of global spatial data (especially the raster data) and can express and process multi-resolution global geospatial data seamlessly.

The importance of studying topological relations between spatial linear objects is expounded. The concepts endpoint, interior, exterior and boundary of spatial linear object are defined on the basis of basic theories of point-set topology, and a formal and perfect model describing topological relations between spatial linear objects is proposed based on that. Fifteen negative rules are putted forward to exclude the impossible topological relations which are described by the model according to the realistic physical meaning of spatial linear objects. The smallest set of topological relations between spatial line objects is proposed, and the exclusivity and perfectibility of the smallest set are proved.

PostgreSQL is a widely used open source object-relational database system, on which the PostGIS spatial database is built. By defining geometry types in PostgreSQL according to the OGC WKB standard, geographic features are usually defined as a base type which is stored as general binary data blocks without internal structures. But the unstructured representation of the structured geometry data model brings the problem of inefficient data access. In this paper, we propose a new approach that uses an array of structured composite types to replace the unstructured base types to store geometry types. Then PostgreSQL 8.3 is extended to support spatial data management in this proposed approach following the standard of OGC's Simple Feature Specification. A contrastive experiment proves the advantages and efficiency of this method.

Metadata is important to facilitate data sharing among Geospatial Information Communities in distributed environment. For unanimous understanding and standard production of metadata annotations, metadata specifications are documented such as Geographic Information Metadata Standard (ISO19115-2003), the Content Standard for Digital Geospatial Metadata (CSDGM), and so on. Though these specifications provide frameworks for description of geographic data, there are two problems which embarrass sufficiently data sharing. One problem is that specifications are lack of domainspecific semantics. Another problem is that specifications can not always solve semantic heterogeneities. To solve the former problem, an ontology-based geographic information metadata extension framework is proposed which can incorporate domain-specific semantics. Besides, for solving the later problem, metadata integration mechanism based on the proposed extension is studied. In this paper, integration of metadata is realized through integration of ontologies. So integration of ontologies is also discussed. By ontology-based geographic information semantic metadata integration, sharing of geographic data is realized more efficiently.

Cardinal direction relation is an important spatial relation to determine directions and locations between spatial objects. Since 1987, some corn-based and projection-based direction relation models have been proposed. However, these existing models use different terms and methods to describe and represent direction relation, so it is difficult to share information in application systems. In order to support cardinal direction relation representing and reasoning according to explicit different level of details and improve the information reusing and interoperability, it is necessary to have explicit formalizations of mental concepts that people have about it. In this paper, we use ontology to set up a higher level of abstraction where the more valuable information about the meaning of the direction relation can be handled, and propose an extended qualitative description and reasoning cardinal direction model, which precisely describes cardinal direction relations between objects by separating the reference objects as point, line and area. This model has been implemented based on geo-ontology, and it can support common direction relation applications in spatial reasoning domain.

Spatial database is an essential component of Geographic Information System (GIS). With the development of modern remote sensors and data acquiring instruments, the amount of spatial data increases with geometric series. Retrieval required data in such massive database is a challenging issue to database engineers. Therefore, building efficient index is significant to spatial database. In this paper, bitmap index technology, which is rarely used in spatial database, is taken into consideration. In this paper, TM/ETM+ images covered main land of China are selected to establish a spatial database. In order to rapidly inquire and retrieval required data from the spatial database, an effective spatial index is very important. A bitmap index solution for original TM/ETM+ image is advanced in this paper. The bitmap index schema, which indexes field by building "0" and "1" binary bit vectors, is designed based on analyzing its principle and applicable conditions. In the image database, the strategy is programmed to implementation and applied for data retrieval. So that complex querying operations can be transformed to bitwise logical operations. A users' interface is developed based on building such bitmap index for original TM/ETM+ images database. Then the paper probes into the bitmap index update mechanism to address problems resulted from inserting and deleting images operation. In order to address the problem of high cardinality, an encoded bitmap index technology is proposed as well. At last, a simple comparison and efficiency analysis is carried out to illuminate its applicability.

The revision of geographical data is still one of the major open challenges for the successful implementation of Geographic Information Systems (GIS). Nowadays, Geographic Information Systems are considered to be truly analysis and decision-making tools. For that reason, a growing number of organizations invest in such systems and add specific information necessary to the tasks for which they have the responsibility. Spatial data are the backbone of GIS analysis, but only current and accurate spatial data can provide the appropriate framework for successful use of GIS technology. Out-of-date or inaccurate spatial data could contaminate GIS results in direct correlation to the obsolescence and inaccuracy of the spatial data. There is a great need for cost-efficient spatial data revision and quality control methods in order to update the master and user spatial databases, fulfilling the request of the most faithful image of the geographic space reality. This paper tries to provide a review of latest achievements on Spatio-temporal Data Revision (SDR). A comparison of three popular revision models is given in detail.

The integration of heterogeneous geospatial data offers possibilities to manually and automatically derive new information, which are not available when using only a single data source. This paper presents a three-level schema integration architecture which consists of local schemas, mapped schemas, and a global schema, for global heterogeneous geospatial systems. we describe a machine-learning based approach for GIS schema matching. Our approach extends existing machine-learning approaches for (traditional) data mapping but departs from them due to the nature of geographic data. Our solution reduces the complex mappings by identifying different values of a determining property.

Side-scan sonar is a remote sensing technology for submarine geological and geomorphological information detection, which provides acoustic imaging of the bottom at rates of up to several thousand square kilometers a day. How to manage so abundant and tremendous data has become a new problem, urgently needs to be resolved. As side-scan sonar image, also known as sonograph has an inherent geometric distortion which is so-called slant-range effect. Otherwise, the original side-scan sonar image is characterized as an order of scanning lines, without geographical position integrity and scalability. All this requirements and factors are considered and the correction of slant range distortions is outlined. This approach provides a management mechanism of raster catalog for series of sonar images of a surveying zone. Against the efficiency problem of massive image data storage, a spatial database engine is improved from such aspects as tile size setting, image resampling also called pyramid creation and spatial index establishment and so on, so as to enhance performance and improve access rate. The fact is that it archived an ideal response time and is proved to be more effective.

The XML-enabled Spatial Visualizing Database can be widely used because of its high security and convenience of management. It is often implemented by relational databases. But, these databases can't index points, curves and surfaces separately based on their characteristics. In addition, the indexing systems of these databases are not capable of creating the function of indexing on a wide range of relational databases. These limitations were solved by the following two steps in the paper. Firstly, referring to the SVG spatial expressional model, bring up a solution to index points, curves, and surfaces separately with different algorithms. Secondly, elaborately design a spatial indexing system with high cohesion and low coupling by using three design patterns: Template Method, Bridge and Adapter. Eventually, our system has three achievements: 1) separately index points, curves and surfaces with different algorithms catering for the users; 2) index SVG visualizing data on heterogeneous relational databases; 3) many of the open-source spatial indexing projects can be used in this system after modifying some codes. Experiments have been carried out to prove the conclusions mentioned above.

The historical information could be managed by TGIS which has not been applied in the forest resource management. The Spatio-temporal data model is the core of TGIS. By referencing from several existing Spatio-temporal Data Models and analyzing the characteristics of the forest resources data, this paper proposes a new Spatio-temporal Data Model of forest resource named "multi base states model based on feature and event". It is proven efficient in managing and retrieving the forest historical information.

Rapid land use change has taken place in many coastal regions of China such as the Pearl River Estuary over the past tow decades due to accelerated industrialization and urbanization. In this paper, four temporal Landsat TM images were used at a spatial resolution of 30m to mapping wetlands and monitoring their changes in the Pearl River Estuary for the time period of 1988-2004. Hierarchical classification method based on spectral data, prior knowledge about the study area and GIS ancillary data were used to acquire four temporal wetland distribution maps, and three evaluation indicators (change ratio, change speed, and bidirectional dynamic degree model) were used to analysis the change characteristic of wetlands in the study area. The result indicated that there has been a rapid decrease of wetlands in the study area during 1988-2004. The total area of wetlands has lost about 122.66 km2 in the Pearl River Estuary.

In this paper, we took into account both the spectral information and the spatial information and estimated how well the needed information contained within the multispectral (MS) and panchromatic (PAN) images was represented by the pan-sharpened image. Based on that, we proposed a new quality index which could be seen as an expanded index of the global quality measurement Q4. In our method, we first measured the spectral information preserving quality between the MS image and the fusion result. Then, we constructed a virtual spatial detail image considering the spatial resolution ratio between the source MS image and the PAN image, and also extracted the detail image contained in the merged image using the same technology, followed by a spatial information preserving quality index calculated from these two detail images. At last, we integrated the two indices by means of weighted addition determined by fusion model. To illustrate the superiority of this new index, we took experiments on two pairs of ZY-2 PAN and ASTER MS (1 2 3 bands) remote sensing imageries, and adopted the tradeoff FIHS fusion method in which the tradeoff parameter was set to different values standing for different fusion models. After using the proposed index to assess the quality of fusion, we think that the new index is compliant with subjective evaluations and could therefore be used to compare different image fusion or to find the best parameters for a given fusion model. Finally, we gave an experiential weight parameter of the quality index while assessing the tradeoff FIHS fusion with images from these two sensors by the author's experiments.

Digital Elevation Model (DEM) is indispensable for much analysis such as topographic feature extraction, runoff analysis, slope stability analysis, landscape analysis and so on. Such analysis requires a high accurate DEM. The accuracy of DEM is usually represented by spatial resolution and height accuracy. Slope is one of the crucial terrain variables in spatial analysis and land use planning, especially in the mountain region which is suffering from serious soil erosion. However slope accuracy derived from DEM usually does not match with its popularity. A quantitative simulation to slope uncertainty is important not only theoretically but also necessarily to applications. The objective of this study was to analyze the slope uncertainty of Yizi following GIS based on different DEM resolution. Comparative and math-simulation methodology was employed for data processing and analysis. There is a linear correlativity between mean slope, slope change rate and different DEM resolution within the study area, and the analysis and simulation result shows that different DEM resolution has great influence on slope uncertainty. This methodology applied in this study should be helpful to similar researches in spatial data uncertainty investigation.

The theoretical models of positional uncertainty of vertexes have been derived from overlay of the error ellipse models that are considered as the positional uncertainty models of line endpoints. Using probability theory and simulation tests, we mainly study the positional uncertainty characteristics of manual digitization vertex. The research results are as follows: first, using the method, that is sequentially digitizing a series of vertexes with different turning angles, repeating about six hundred times, we can get the stable distribution of frequency of digitizing points; second, in the direction of the angular bisector of turning angle, with the value of turning angle increased, the digitizing points from digitizing vertexes have a trend for gather, and the frequency distribution whose peak is less than three shows skewness, while in the direction of the perpendicular angular bisector of turning angle, digitizing points of vertexes with the acute turning angles are more concentrated than the ones with obtuse angles, and the distribution performs a state of symmetric but not the standard normal distribution; third, two dimensional uncertainty model of digitizing vertexes whose plane projection is a type of irregular geometric shape is a joint distribution model combined by skew distribution and approximate normal distribution.

The small satellite constellation for environment protection and disaster monitoring (HJ satellite constellation) is facilitated to satisfy the country and surrounding countries or regions' need of dynamic monitoring and forecasting environment and disaster through the use of remote sensing. HJ-1A and HJ-1B will be launched in 2008 and the ground system of which is being developed in accordance with the technical demands of their owners. The quality of data acquired by onboard sensors is essential to effective application of the data, which is also a measure of the success of the engineering and science efforts of operational satellite program. To systematically monitor and measure the sensors' in flight performance and data quality, we designed an integrated Data Quality Analysis and Assessment System (DQAAS) for HJ satellite constellation's ground system, and are developing a demonstrating DQAAS system, which is also a part work of Sky-To-Earth System of Systems (STESS). This paper first analyzes the necessities to include a Data Quality Analysis and Assessment System in the ground system of HJ satellite constellation. Upon the analysis of the function requirements of DQAAS, the framework and structure of DQAAS is presented. The operation flow and interfaces definition is very important for an integrated system, which is also included in the paper. At last, the functions and algorithms of Data Quality Assessment Subsystem are introduced in detail. We expect to promote the quality and analysis and assessment technology in China through the development of DQAAS for HJ satellite constellation.

As one of key factors which control the spatial soil variation in soil-landscape model, terrain information includes not only topographic attributes (such as slope gradient, curvature, etc.) but also information of slope positions. But the spatial gradation of slope positions is still not quantitatively considered in current predictive soil mapping and other related application areas. The issue of this paper is to make a primary discussion on the potential role of spatial gradation of slope positions in soil-landscape model. Taking a study area in Northeast China and a detailed taxonomy of slope position, this paper firstly utilized a fuzzy inference approach based on similarity to the typical locations to quantify the spatial gradation between slope positions. Secondly, we took use of the soil-subgroup map in study area to analyze whether there is an evident relationship between soil distribution and spatial gradation of slope positions or not, by means of the statistics on the percentage of slope positions on where each soil subgroup in study area is distributed. The results show that the distributions between slope positions and soil subgroups are clearly correlative in the areas where fuzziness as one certain slope position is little. And the soil distribution shows obvious intergradation and uncertainty in areas where the slope position is identified with much ambiguity. The evident relationship between soil distribution and spatial gradation of slope positions indicates that the quantitative information of spatial gradation of slope positions should be included into both soil-landscape model and its applications (e.g., digital soil mapping, etc.), for a better depiction on the co-variation between slope positions and soil type.

In satellite mapping application area, geometric quality assessment for remote sensing image compression is of great importance for onboard compression index determination. The paper proposed an integral geometric quality assessment plan for remote sensing image compression, which includes image matching accuracy assessment, effects of compression on automated DSM/DEM extraction, and photogrammetic point determination accuracy assessment. Image matching accuracy analysis shows how degradation in image quality associated with lossy compression can affect matching accuracy. In analyzing effects of compression on automated DSM/DEM extraction, a DSM is extracted from the original stereopair and held as the reference against which the terrain heights obtained from compressed imagery are compared. Similar to DSM extraction accuracy analysis, photogrammetric point determination accuracy analysis is proposed to compare the accuracy of two sets of 3D coordinates of the feature points which are from original images and reconstructed images. The relationship between compression ratio and terrain types was examined. As to SPIHT algorithm adopted in Resources Satellite-3, the experiment results showed that the compression ratio should be no more than 4:1 for mapping application.

In order to develop a quality assurance system for maps thus obtained from the National Western Surveying and Mapping Project on 1:50000 Topological Maps Blank Area, a spatial data quality check method based on entity and evaluation method by implementing the cloud theory and rough set is going to be put forward in the paper. First, spatial data quality problems are to be analyzed and possible quality problems will be described. Secondly, a digital linear graphic spatial data quality model is built and the quality elements and sub-elements are elaborately summarized. Next, spatial computing operators that the check process demands are given. The weight of each index is calculated according to importance of attribute in rough set. Cloud decision generator transforms indexes value into qualitative evaluation. Finally, the homologous software of the spatial data quality check and evaluation is developed to control spatial data quality. Therefore a spatial data quality control and evaluation technique system is founded. It shows that the check and evaluation methods are feasible and software has higher automation from the experiment.

Spatial relation theory is one of the hottest research topics in the GIS circle both at home and abroad. This research intends to analyze relevant research findings over the past more than a decade and latest academic development to point out major problems and inadequacy in existing researches, focusing on the topological relations and uncertainty in GIS to engage in a systematic investigation. This research discusses the present situation of the overall GIS field, the development of GIS, and features of the present development of GIS technology. It also investigates and analyzes relevant issues, such as the uncertainty in topological relations which is caused by the inaccuracy of, and uncertainty in, GIS spatial data, spatial reasoning, spatial searching, spatial-searching language, image segmentation, the theoretical development of topological relations, the trend of GIS development, and the problems in the development of GIS in the 21^st century. The "egg-yolk model" is formulated. The "egg" is the maximum range of the fuzzy target while the "yolk" is the minimum range of the fuzzy target and the "white" is the scope of the uncertainty.

Research on positional uncertainty of point is the basis of modeling uncertainty of line segment and polygon. The positional uncertainty indices of point have been widely studied in topography and metrology. In this paper, the exist entropy uncertainty interval of one-dimensional random variable is extended to the circumstances of two-dimensional, three-dimensional and N-dimensional by introducing the theory of information entropy. The indices of entropy uncertainty ellipse, entropy uncertainty ellipsoid and entropy uncertainty super ellipsoid are presented, which can be considered as the indices of uncertainty degree of the random point in two-dimensional, three-dimensional and multidimensional. The entropy indices presented in this paper are unaffected by the objective selection of the confidence level. And they are especially suitable for uncertainty measurement of the random points with unknown distribution in GIS.

The realization of map functions is usually paid much more attention to than the visualization quality of map in the development of electronic map. As a result, the visualization effect of electronic map is unsatisfactory. The visualization quality of electronic map is directly related to user's understanding of geographical information and influences the application of electronic map. Along with extensive expansion and application of electronic map, visualization effect of electronic map has already become an important aspect to evaluate electronic map products. To examine the evaluation and the control techniques of electronic map visualization quality and to establish evaluation standards of electronic map visualization quality are of great significance at present. Based on the experiences in electronic map design, development of electronic map platform and professional application, the authors summarize several factors affecting visualization quality of electronic map: user interface, display capacity, visual effect, display speed, dynamic labeling, real-time display, legend and symbol design, and other aspects including temporal effect, mark effect, dynamic generalization, and dynamic projection. Combining with the practice in developing an electronic atlas system called eMapSee, the authors analyze related control techniques of visualization quality of electronic map from these aspects: friendly user interface, legibility and beauty of display effect, fast map display, real-time map display, and introduce how these techniques are used in practice.

Land based mobile mapping technology (MMT) can collect spatial and attribute data in high efficiency and the data can meet the requirement of 1:2000 scale or even higher accuracy topographic mapping without ground control point. In mobile mapping, direct georeferencing by the integration of GPS and INS/DR provides the mobile platform's continuous position and pose to mapping sensor in field survey, then image stereo of the certain target is used to calculate its 3d global coordinates. But in general, current MMT image stereo is defined as the solid baseline between the different CCD cameras' relative position deviation which is rigid connected to each other and calibrated by high precise control field, and baseline length is quite short (less than 2 meters). This brings some troubles on the far distance target or big size building observation from different viewpoints, and also limits the use of huge amount of MMT measurable images. This paper presented the image stereo pair construction in soft-baseline condition, which is organized through the different imaging time and platform field place but overlapped to the certain target, thus the baseline's accuracy would be some obvious lower than the solid one. We made a brief introduction about Tongji Geo-Informatics MMT firstly, analyzed the image stereo pair from the solid-baseline, and then constructed MMT measurable image into soft-baseline stereo and due mathematical model is expressed. In the paper's experiment part, we analyzed the concrete target 3d solution with the total station, MMT image's solid-baseline stereo and the soft-baseline surveying. The calculation shows that the target 3d coordinates solution in soft-baseline has the same precision as the solid one, also meets the topographic mapping requirement of scale 1:2000. Last, the paper discussed some important influence from the change of angle of two observing bundles in photogrammetric forward intersection and the change sub-deviations of survey error vector in image space coordinate system. As conclusion, MMT soft-baseline brings more choice with target survey in the larger observing distance and good coordinate solution with the measurable MMT images.

This study put forward an integrated evaluation model. Bases on a framework of fuzzy set theory and entropy theory, we firstly complete the classification using fuzzy surveillance approach, taking it as a formalized description of classification uncertainty. Then introduce hybrid entropy model for classification uncertainty evaluation, which can meet the requirement of comprehensive reflection of both random and fuzzy uncertainty, meanwhile construct evaluation index from pixel scale with the full consideration of different contribution to error rate of each pixel. Finally, we use such method to evaluate land-use classification result of remote sensing image, which is in Huangshi city, Hubei province of China, by using hybrid entropy evaluation model, the classification quality can be fully reflected, and pixelscale evaluation indexes were easier constructed.

The real world is an infinite complex and very huge systems, the phenomenon and processes in this world have many complex relations among them. It is consecutive and cannot be treated as a determined one as the traditional geographic information system does; What's more, the uncertainty and fuzziness exist in every stage of data processing of GIS, from data collection, data storage to data analysis etc, so it is very meaningful to apply fuzzy theory in GIS for its ability to handle fuzziness and uncertainty of spatial data. The paper talks about the current situation of fuzzy theory applied in GIS, including the classification of application fields, its main methods, principles etc. The detailed fields we concerned include spatial object modeling, spatial reasoning, spatial analysis, spatial data mining, and reliability analysis of GIS data and so on. Furthermore, we put forward some development foregrounds and research orientations of fuzzy theory applied in GIS.

Remote Sensing is the acquisition of information about an object without touching it. Remote sensing data and image analysis are used as major tools in investigating natural formations and man-made structures. Remote sensing techniques have proven to be very useful in the search for archaeological sites. Techniques such as aerial photography, colorinfrared photography, thermal infrared multi-spectral scanning, and radar imaging have successfully been used to locate potential archaeological sites and add questions to known sites. Image fusion, defined by Franklin and Blodgett (1933) as the computation of three new values for a pixel based on the known relationship between the input data for the location in the image, has been advocated in a large number of papers as a suitable technique to improve the spatial appraisal of an image produced by merging low spatial resolution data with high spatial resolution data. The different images to be fused can come from different sensors of the same basic type or they may come from different types of sensors. The composite image should contain a more useful description of the scene than provided by any of the individual source images. In our work, the simultaneously acquired SPOT5 multi-spectral images and SPOT5 panchromatic images are collected. First of all, the geometric correction is conducted to all the images with the error less than 0.5 pixels to make sure the high quality of image fusion. Then image fusion in pixel lever is performed and the image fusion quality is assessed by different criteria.

While in land spatial data processing or application, spatial relationship of land data features should be carefully checked to guarantee the data quality. For land use data or cadastral data, lots of spatial relation rules need GIS query functions to find the overlay or disjoint feature errors, for example, all the land use patches must conform to combine a non-overlay, non-repetition and continuous area. Currently, there are many types of spatial relationship like equality, contain, intersect, disjoint, overlay, contact etc, which can be utilized in GIS systems. Though each of them can find different data errors, they require in turn examining every pair of features separately and will be very time-consuming, especially when land use data contains large number of features or lots of the feature shapes are complicated, so for land spatial data management system, a fast algorithm is needed to systematically check variant data errors in a short time. In this paper, a new land data checking algorithm of overlay, repetition and disjoint errors is proposed. The main concept and detail steps of this algorithm are introduced and illustrated. Then an experiment on comparing this algorithm and a common algorithm which uses spatial query functions of GIS software in checking overlap, repetition, and disjoint errors for land use data is carried out. Results show that this algorithm has high efficiency than the other one.

Models are often thought as the abstraction of object, phenomenon, system and process. But the present model base system is good at the abstraction of process which starts from the input data to the results. And it falls short of the model composition. Based on the object-oriented methods, this paper aims to discuss a new application-oriented model base system. The structure of model interface parameter is abstracted into descriptive model (DM) which can be regarded a bridge between different models. Using object-oriented method, a series researches has been made focused on DM, and establish the application-oriented model-base system. The model working flow and user-oriented model inheritance mechanism were designed for applying and maintaining the model resource easily. A prototype system was designed and developed, and an application demonstration is shown to verify its feasibility.

Back-propagation neural network model (BPNN) is an intelligent computational model based on stylebook learning. This model is different from traditional adaptability symbolic logic reasoning method based on knowledge and rules. At the same time, BPNN model has shortcoming such as: slowly convergence speed and partial minimum. During the process of adaptability evaluation, the factors were diverse, complicated and uncertain, so an effectual model should adopt the technique of data mining method and fuzzy logical technology. In this paper, the author ameliorated the backpropagation of BPNN and applied fuzzy logical theory for dynamic inference of fuzzy rules. Authors also give detail description on training and experiment process of the novel model.

This paper discusses the importance of sampling in Geographic Information Systems (GIS), and briefly summarizes the classical sampling theories of simple random sampling, systematic sampling and stratified sampling. The main purpose of this paper is to introduce the architecture of spatial sampling software named as Sandwich Spatial Sampling Package. In this software, the steps of sampling include calculating sampling size, distributing samples, calculating and displaying sampling results. The first step can be divided into four parts: setting configuration files, selecting sampling fields and relative parameters, inputting parameters to calculate sampling sizes and displaying calculated results to help users choose the best function to calculate sampling size.

Chinese address geocoding is a difficult problem to deal with due to intrinsic complexities in Chinese address systems and a lack of standards in address assignments and usages. In order to improve existing address geocoding algorithm, a spatial knowledge-based agent prototype aimed at validating address geocoding results is built to determine the spatial accuracies as well as matching confidence. A portion of human's knowledge of judging the spatial closeness of two addresses is represented via first order logic and the corresponding algorithms are implemented with the Prolog language. Preliminary tests conducted using addresses matching result in Beijing area showed that the prototype can successfully assess the spatial closeness between the matching address and the query address with 97% accuracy.

The paper intends to employ Geographic Information System (GIS) and Bayesian Network to discover the spatial causality between enterprises and environmental factors in Beijing Metropolis. The census data of Beijing was spatialized by means of GIS in the beginning, and then the training data was made using density mapping technique. Base on the training data, the structure of a Bayesian Network was learnt with the help of Maximum Weight Spanning Tree. Eight direct relations were discussed in the end, of which, the most exciting discovery, "Enterprise-Run Society", as the symbol of the former planned economy, was emphasized in the spatial relations between heavy industry and schools. Though the final result is not so creative in economic perspective, it is of significance in technique view due to all discoveries were drawn from data, therefore leading to the realization of the importance of GIS and data mining to economic geography research.

This paper first discusses the necessity of the automatic annotation placement. According to the Chinese custom of reading map, based on the present principle of map annotation placement, a new principle is proposed. Then some present algorithms of automatic map annotation placement are introduced and, at the same time, their shortcomings are pointed out. In order to improve the automatic annotation placement, the authors bring forward an automatic annotation placement algorithm of point feature based on template. The template is explained and described by figures. Then the automatic placement process using the template algorithm is detailed. At last, this paper shows the experimental result based on the new algorithm and makes some useful conclusions.

With quick development of economy, spatial distribution and specialization level of China large scale commodity exchange markets whose turnover are more than 100 million Yuan, have changed greatly. And influencing factors which distribute in the research region have attribute information and spatial information and do not satisfy statistical independence. Commodity exchange market specialization index is brought forward to measure specialization degree, based on the former research and constrained co-local spatial association rule is used to analyze symbiotic pattern between specialization level and influencing factors. Constrained predicate templates and association rule templates can improve mining efficiency greatly. As the result shown, large scale commodity exchange market specialization level on country-region spatial scale went down from 2000 to 2005 and rose at 2006. The interesting association rules extracted based on defined minimum support and confident can provide officers of region governments with rational advices on large scale commodity exchange markets planning and construction.

In this paper, a new indirect georeferencing method for linear array imagery is presented. The new method fully utilizes the original orientation elements directly measured by geopositioning system carried on the satellite. First the systematic errors contained among linear and angular elements were modeled by second order polynomial functions depending on time. The constant terms compensate the shifts and angular drifts between the image system and the GPS and star sensor system. The linear and quadratic terms model the additional systematic errors. There are 18 parameters which should be estimated for image georeferencing. Considering the strong correlation among those orientation parameters, they were treated as virtual observations and the weights were assigned according to prior-knowledge such as the precision of sensor position and attitude observations. By this step, the value change of orientation parameters in adjustment process can be constrained reasonably. The new method has been tested on two scenes of CBERS-2-3 satellite images. In the tests, the location accuracies of 15~25m for planimetry have been obtained using the adjusted orientation elements, greatly improved compared to the direct georeferencing results. Actually, the results should be even better if the measuring errors of image point can be further reduced.

The distributions of irradiance on the image plane decrease away from the center of the image even if the scene is a uniform white field. This crucial problem is posed in digital image processing, such as edge detection and stereo matching. This paper presents an edge detection method of non-uniform illumination image which uses fitting calibration algorithm to correct the non-uniformity and wavelet transform to extract edges from the images corrected. The experimental results demonstrated the validity of our theoretical model and the effectiveness of wavelet transforms based edge detection of non-uniform illumination image.

An algorithm for automatically matching corresponding points on vector map features is put forward in this paper. Firstly, a feature simplification approach resembles Douglas-Peucker algorithm is designed to simplify geometrical entities, but here the offset threshold of Douglas-Peucker algorithm is substituted by similarity coefficient threshold defined in this paper. This approach can ensure that simplification result of map feature is invariable to similarity transformation if only the value of similarity coefficient does not change. Secondly, this algorithm extracts convex hulls of boundaries of map features which have already been simplified. Lastly, the corresponding points on the convex hulls can be recognized and matched automatically according to pre-defined matching rules. The matched corresponding points are critical points which distribute uniformly along the boundary of map feature. The experiments indicate that this algorithm is efficient and can be applied in the field of map conflation.

Global warming and climate changes are changing the environment and therefore changing the distribution and behaviour of the plant species. Plant species often move and change their distributions as they find their original habitats are no longer suitable to their needs. It is therefore important to establish a statistical model to catch up the movement and patterns of the endangered species in order to effectively manage environmental protection under the inevitable biodiversity changes that are taking place. In this paper, we are focusing on the population category of rare Proteas that has an estimated population size from 1 to 10 per sample site, which is very small. We used the partial differential equation associated regression (PDEAR) model, which merges the partial differential equation theory, (statistical) linear model theory and random fuzzy variable theory together into a efficient small-sample oriented model, for the spatial pattern changing analysis. The regression component in a PDEAR model is in nature a special random fuzzy multivariate regression model. We developed a bivariate model for investigating the impacts from rainfall and temperature on the Protea species in average sense in the population size of 1 to 10, in the Cape Floristic Region, from 1992 to 2002, South Africa. Under same the average biodiversity structure assumptions, we explore the future spatial change patterns of Protea species in the population size of 1 to 10 with future (average) predicted rainfall and temperature. The spatial distribution and patterns are clearly will help us to explore global climate changing impacts on endangered species.

With the development of remote sensing satellites, the data quantity of remote sensing image is increasing tremendously, which brings a huge workload to the image geometric rectification through manual ground control point (GCP) selections. GCP database is one of the effective methods to cut down manual operation. The GCP loaded from database is generally redundant, which may result in a rectification slowdown. How to automatically optimize these ground control points is a problem that should be resolved urgently. According to the basic theory of geometric rectification and the principle of GCP selection, this paper deeply comprehends some existing methods about automatic optimization of GCP, and puts forward a new method of automatic optimization of GCP based on voronoi diagram to filter ground control points from the overfull ones without manual subjectivity for better accuracy. The paper is organized as follows: First, it clarifies the basic theory of remote sensing image multinomial geometric rectification and the arithmetic of how to get the GCP error. Second, it particularly introduces the voronoi diagram including its origin, development and characteristics, especially the creating process. Third, considering the deficiencies of existing methods about automatic optimization of GCP, the paper presents the idea of applying voronoi diagram to filter GCP in order to complete automatic optimization. During this process, it advances the conception of single GCP's importance value based on voronoi diagram. Then by integrating the GCP error and GCP's importance value, the paper gives the theory and the flow of automatic optimization of GCPs as well. It also presents an example of the application of this method. In the conclusion, it points out the advantages of automatic optimization of GCP based on the voronoi diagram.

Recently, JPEG High Dynamic Range (JPEG-HDR) remote sensing images have become popular in photogrammetry and remote sensing for its high brightness level. But how to reproduce and visualize such images in the standard display device becomes a question, a new tone mapping method in this paper is proposed to realize the visualization of the HDR remote sensing image. The experimental results presented in the paper demonstrate the fast and effective of our method.

Spatial clustering is the process of grouping similar objects based on their distance, connectivity, or relative density in space, which has been employed for spatial analysis over years. To be able to integrate the proper clustering methods in geospatial information systems, two problems are discussed in the paper: how to select a proper spatial clustering methods and how to implement the clustering method in GIS. In this paper, we will give a detailed discussion on different types of clustering methods. Analysis on advantages and limitations for some classical clustering methods are given. Then we will discuss some issues of using the spatial clustering methods in the geospatial information systems.

In this paper a new technique of objects measurement based on multi-wavelength lidar system has been proposed and developed to make horizontal-path laser measurements of objects. The two or more wavelengths laser transmitter operates within and adjacent to the sensitive bands exhibited by the characteristics of each object, the result could be used to establish inversion models of the laser transmitting backscatter signals. The application value and the key techniques of the spectral lidar are analyzed. The lidar wavelength selection method is studied and a hyperspectral experiment had been down to testify the feasibility of the theory. Also issues to approach the final goal of this new technique are discussed.

With a wide use of vector maps, the copyright issue is educing an increasing importance and attracting focus on the transmission and the exchange of the vector maps through a network environment. This paper discusses a feature nodes based watermarking method (FNBW) towards keeping robustness and high accuracy of digital map based on SVG and GML format. The digital map treats as a set of curves in the embedding algorithm, and each curve was divided up into several shorter curves under two given thresholds. And then a watermark bit combined with user certificate was embedded into each segment around the feature nodes with the maximum curvature in the segment series nodes. To extract the watermark, all watermark nodes were calculated and searched for in the watermarked map with the Watermark node Searching Algorithm by using the original map. Finally the method calculates the similarity between the original watermark bits and the extracted ones, and determines whether the watermark exists or not. As the experiment result shown, the method not only guarantees the accuracy of vector map but also possesses the good robustness, such as it gives 1.00 similarity under no attack or only geometric transformation with the map; And the anticopping ability is also good enough to give a more than 0.87 similarity for the map cropped 80%. In addition, the method has the full ability of anti-compression lossless methods and good ability to the loss approaches. And an experiment curve of the similarity threshold was given in the paper, which helped to control the anti-attack ability of the watermark and set parameters for an automatic procedure of watermark detection.

In this paper, a total of 191 topsoil samples were taken in Tongyu County, a typical area of farming-pastoral ecotone in the Northeast China, and soil organic carbon (SOC) concentrations were investigated using statistics, geostatistics and GIS techniques. Mean concentration of SOC in surface soil of Tongyu County was 0.76%, which was a very low level. The coefficient of variation (C_v) (0.23) indicated the moderate variability of SOC. Significant positive correlations existed between SOC and total N, total P, available N, silt, clay, respectively; negative correlations between SOC and sand, SOC and elevation were observed. The linear regression model of SOC was built based on other soil properties in order to comparing with interpolation results. To obtain an unbiased assessment on the spatial structure of SOC, the spatial outliers were detected using local Moran's I index. The parameters of experimental model fitted for the dataset excluded spatial outliers were better than those for all samples, but the difference was not significant at the regional scale. Based on Kriging interpolation, the spatial distribution of SOC showed a broad regional pattern, with higher values in the eastern part, and lower values in the middle and western part. This spatial pattern was mainly controlled by structural factors, such as climate, parent material and topography.

Conversion and sharing of spatial data from different departments is an essential part of information construction in China. The first step of the solution is to match place-name data. However, there are administrative changes in some places with the development of urbanization process. It undoubtedly increases the difficulty to match place-name data. In the daily work, the data are artificially matched with available place-name database and materials such as graphs and record cards. Although it is easy to put in practice, this method may cost a lot of time and labor to keep the accuracy. The algorithms for matching strings can be used to solve the problem. But most of them focus on solving the English strings match problems and less refer to Chinese. In the paper, BPM-BM (Bit-Parallel Matrix -Boyer Moore) algorithm, the most efficient filter method for approximate string matching of Chinese text, is proposed to match place-names between the national surveillance sites of infectious diseases and the 1:1, 000, 000 scale township map of China in 2000. The study indicated that the proposed method decreased artificial process greatly and the accuracy which achieved 94.2% was higher than the SQL commands method.

Spatial information plays an essential role on the progress of science and technology, and has a profound impact on economic growth and society progress in the twenty-first century. Spatial knowledge representation and reasoning are very important for us to utilize spatial information. In this paper, a review is presented on spatial knowledge representation and reasoning. And then we propose a method of spatial knowledge representation and reasoning based on Bayesian networks. We focused on how to represent spatial relationship, spatial objects and spatial features by using Bayesian networks. Let spatial features (or spatial objects, spatial relationships) as variables or the nodes in Bayesian network, let directed edges present the relationships between spatial features, and the relevancy intensity can be regarded as confidence between the variables (the same as probability parameter in Bayesian network). Accordingly, the problem of spatial knowledge representation will be changed to the problem of learning Bayesian networks. The experimental results are given to verify the practical feasibility of the proposed methodology. Eventually, we conclude with a summary and a statement of future work.

Spatial autocorrelation has been proved to be a useful tool in many fields, including spatial heterogeneity research and spatial structure investigation. With the increasing of remote sensors, images of different resolutions are being acquired and put into usage. So how to select images of appropriate spatial resolution becomes to be a great challenge. Therefore, it's necessary to investigate the scale dependence of the spatial autocorrelation in remotely sensed images, as Jupp et al (1989) has declared that the spatial autocorrelation in an image is related with the spatial resolution. In this paper, panchromatic band of the QuickBird imagery is aggregated into a series of images of coarser spatial resolution and used to investigate the scaling effects. Both global and local spatial autocorrelation measures at different scales are calculated. Results show that global autocorrelation increases as the resolution becomes coarser and lag distance decreases. Local autocorrelation shows dependence on scale and the land cover type. It's necessary to combine global and local measures together to explore the intrinsic of spatial autocorrelation.

In order to solve the current problem of the sunlight analyzing models, which are not suitable for most of the mountainous and hilly areas because of ignoring the factors that the topography influences the sunlight, this article will integrate the principles and ideas of "Shadow Equivalence", "Reverse Sunlight" and "Sky Graph", and will propose "Backlighting Vector Intersecting Shadow Projection SurFace Model" (BVIFM), from the angle of the Geometrical Optics. Besides, this article will use a certain residential district in Chongqing Province and the actual terrain data (DEM) as examples to verify the validity and correctness of the BVIFM .The results from the experiments show that the BVIFM can be quite satisfactory, while calculating the sunlight effects caused by the uncertain mountains and hills on their neighboring constructions. The proposal of the BVIFM can not only remedy the shortcomings of the current models, but also provides a new solution for the sunlight calculation as well as laying a foundation of a unified model of the sunlight analysis.

Based on "3S" (RS, GIS, GPS) technologies and completely distributed design ideas, a new algorithm of the Distributed Snowmelt Concentration Model is designed and built after study the Distributed Snowmelt Runoff Model. It has spatiotemporal features and takes the DEM data, which with high resolution, as a foundation and picks up the hydrological factors, such as slope, gradient, direction of flow, collecting time, drainage network etc., and the algorithm is simple to understand and to implement, requiring only a few tens of code lines and running faster. So the algorithm will be versatile. Meanwhile, a new conception "Period Unit of Time-step" is put forward in this paper, and the algorithm procedure is fully detailed too. After the model applied in the representative study area, Juntanghu Basin, which located in the North-Tianshan Mountains, China, and contrasted with the homologous observed data obtained in the same field, the simulation results show clearly that the Distributed Snowmelt Concentration Model and its algorithm is very good.

Monitoring the Earth using imaging spectrometers has necessitated more accurate analyses and new applications to remote sensing. A very high dimensional input space requires an exponentially large amount of data to adequately and reliably represent the classes in that space. On the other hand, with increase in the input dimensionality the hypothesis space grows exponentially, which makes the classification performance highly unreliable. Traditional classification algorithms Classification of hyperspectral images is challenging. New algorithms have to be developed for hyperspectral data classification. The Spectral Angle Mapper (SAM) is a physically-based spectral classification that uses an ndimensional angle to match pixels to reference spectra. The algorithm determines the spectral similarity between two spectra by calculating the angle between the spectra, treating them as vectors in a space with dimensionality equal to the number of bands. The key and difficulty is that we should artificial defining the threshold of SAM. The classification precision depends on the rationality of the threshold of SAM. In order to resolve this problem, this paper proposes a new automatic classification model of remote sensing image using SAM combined with decision tree. It can automatic choose the appropriate threshold of SAM and improve the classify precision of SAM base on the analyze of field spectrum. The test area located in Heqing Yunnan was imaged by EO_1 Hyperion imaging spectrometer using 224 bands in visual and near infrared. The area included limestone areas, rock fields, soil and forests. The area was classified into four different vegetation and soil types. The results show that this method choose the appropriate threshold of SAM and eliminates the disturbance and influence of unwanted objects effectively, so as to improve the classification precision. Compared with the likelihood classification by field survey data, the classification precision of this model heightens 9.9%.

Rule engine technique which is firstly used in business realm because of the quickly changing business environment can be a good solution to the management of geographic knowledge. The objective of this paper is to research how to organize geographic knowledge and reason with rule engine. The rules of Keys to Chinese Soil Taxonomy (3rd edition) are taken as an example of geographic knowledge. The researching results are as follows: (1) Through the review of literature and web resources, we know the advancement of rule engine technique, and finally select NxBRE as the rule engine we use; (2) The rules of keys to Soil Orders are analyzed, and represented in the form of RuleML; (3) Rule customization module and RuleML parsing module are developed; (4) Knowledge base which consists of RuleML files is created with rule customization module, and we finally achieve the goal of automated keys to Soil Orders with NxBRE.

Due to increasing power consumption, heat dissipation, and other physical issues, the architecture of central processing unit (CPU) has been turning to multicore rapidly in recent years. Multicore processor is packaged with multiple processor cores in the same chip, which not only offers increased performance, but also presents significant challenges to application developers. As a matter of fact, in GIS field most of current GIS algorithms were implemented serially and could not best exploit the parallelism potential on such multicore platforms. In this paper, we choose Inverse Distance Weighted spatial interpolation algorithm (IDW) as an example to study how to optimize current serial GIS algorithms on multicore platform in order to maximize performance speedup. With the help of OpenMP, threading methodology is introduced to split and share the whole interpolation work among processor cores. After parallel optimization, execution time of interpolation algorithm is greatly reduced and good performance speedup is achieved. For example, performance speedup on Intel Xeon 5310 is 1.943 with 2 execution threads and 3.695 with 4 execution threads respectively. An additional output comparison between pre-optimization and post-optimization is carried out and shows that parallel optimization does to affect final interpolation result.

The traditional orthophoto rectification often suffers from the problems of building lean and double mapping, etc., which are caused by no detecting the occluded areas, therefore, many improved occlusion detection methods had been discussed to solve these problems, such as angle and height based ray tracing method, angle-based method and Z-buffer method, etc. Angle and height based ray tracing method based on two different DSM models will be discussed in this paper, Experimental results demonstrate that the accuracy based on TIN DSM is better than that based on dense grid DSM.

Land use spatial pattern reflects both the impact of human activities on the process of ecological system and the human activities response to natural condition. Geomorphology condition, which has a close relationship with land use spatial pattern, is a direct and key factor influencing human to use land at the local level. This paper analyses two cases of land use spatial patterns in Hubei province China, Zigui County and Jiayu County, which are exemplary for two different geomorphology conditions, respectively the mountain area and plain model. The land use spatial pattern is analyzed using geographical information system (ArcGIS) and landscape-pattern analysis software (FRAGSTATS 3.3). The results indicate that different land use type has different landscape characteristics. Simultaneity, the same land use type forms different landscape pattern in the dissimilar geomorphology region. Terrain feature, which restrains the possible land use type, is the base for people to decide how to use the land. It is the most direct factor influencing people behavior for land using. Cultivated land is the substratum of landscape class in Plain, while in Mountain area is forestland. Patches of different landscape classes are inlaid the substratum. Comparing with mountain area, there are fewer land use types and inconspicuous substratum of landscape class in plain because of human intensive disturbance. Meanwhile patches in plain possess higher geometrical similarity and lower landscape fragment than in mountain area.

The paper introduces the edge matching method of vector data on the basis of the arbitrary polygon domain. The method contains three steps: (1) the edge matching features district is divided into source features and target features in terms of the edge matching domain; (2) logical edge matching; (3) the automatic combination of attribute fields while physical edge matching. Test analysis indicated that the method of edge matching extends the mapsheet domain of edge matching to arbitrary polygon domain. The edge buffer search reduces the searched data, which greatly increases the search efficiency, and consequently improves the edge matching efficiency and the accuracy rate. The advantages and the procedure of the programs will be elaborated in the paper.

Vegetation coverage is a widely used parameter to measure global and regional environment change. Evaluating the accuracy and efficiency of vegetation coverage using digital photography under various survey points' densities and distribution patterns has an important referential significance for providing an optimized field measurement method. The vegetation field measurement was carried out in a sample with Artemisia ordosica shrubs in Mu Us sandy land using vertical hoisting digital camera, with four densities and nine distribution patterns of survey points. The results showed that: different density of survey points led to a slight accuracy difference, and the precision improves as the density increases. The sample size had great impact on the precision. Different point distribution patterns led to significantly different results. "Diamond" pattern can get relatively higher degree of accuracy with least points and shortest walking distance in field survey. It's the best choice that could meet the requirements of the maximum precision and minimum workload in the vegetation field measurement.

In this paper, a new method is proposed by applying case-based reasoning technique for detecting the ground collapses. The study demonstrates that the high resolution remote sensing images are suitable for monitoring the ground collapses in the study area with karst relief. With the help of object-based image analysis method, the generic algorithm (GA) for optimizing the spatial, shape, spectral, hierarchy and textural features was used in the multi-scale image segmentation with the good fitness value, and then the case library was built for detecting the collapse. The case library is reusable for place-independent detection. The proposed method has been tested in the Pearl River Delta in south China. The result of ground-collapse detection is well.

This paper proposed a scientific work flow system framework to realize information automatically extracted for satellite remote sensing data. The article first discusses the importance of automatic extraction of knowledge for remote sensing data; second, introduces definition, development, and types of scientific work flow technology, and adopt WebService-based technology to building scientific work flow; then, describes the implementation of spatio-temporal work flow management system (STWFMS); finally, two application system of remote sensing data were introduced to demonstrate automated knowledge extraction based on scientific workflow.

According as general houses' prices data, this paper, based on spatial analysis function of Geographic information system(GIS), using semi-variogram of spatial statistics, studies spatial heterogeneity of general houses' prices distribution in Dongguan quantitatively. The results from the analysis indicate: general houses' prices have both spatial autocorrelation and sometime local spatial heterogeneity, it can be found that the spatial distribution of general houses' prices takes on a zonal anisotropy by anisotropic variability analysis, which means that there are different structural characteristics in different directions for general houses' prices distribution; isotropic variability analysis reveals that: the semi-variogram of general houses' prices distribution in Dongguan is best described by spherical model, changes of general houses' prices distribution are affected by both structural and random factors; the ratio of random variance (nugget) to total variance(sill) is 37.5%, therefore the spatial correlation of general houses' prices is a kind of medium correlation with Nugget/Sill being between 25% - 75%, its spatial correlation range is 16.62 kilometres; the ratio of structure variance(partial sill) to total variance is higher than the ratio of random variance to total variance, this means that certain factors' contributions to the spatial variability of houses' prices is more than random factors' contributions.

For numerous spatial applications, land use data are of central importance and have to be available in a spatial data infrastructure for regional modeling. This also counts for the research project TR32 which focuses on SVA modeling in a regional context. The land use data should be organized in a land use information system according to international data standards providing general metadata including information about data quality. Usually, land use data are available from official sources, but they lack the desired information detail for many purposes. For example, in official land use maps, agricultural land use is generally differentiated between arable land, grassland, orchards and some special land use classes like paddy fields. For detailed (agro-)ecosystem modeling, this information resolution is rather poor. Here, disaggregated land use data which provide information about the major crops and crop rotations as well as management data like date of sowing, fertilization, irrigation, harvest etc. are needed. The analysis of multispectral, hyperspectral and/or radar data from satellite or airborne sensors is a standard method to retrieve such kind of information with remote sensing methodologies. By using a Multi-Data Approach (MDA), the retrieved information from remote sensing analysis is integrated into official land use data by GIS technologies to enhance both the information level (e. g. crop rotations) of existing land use data and the quality of the land use classification.

The central area of a city is an important functional unit in many urban studies. It is a region where business concentrates and municipal facilities densely distribute. Traditionally, statistics of economic and social phenomena can be used to delimitate their boundaries. However, traditional methods based on economic and social investigation are labor-intensive and sometimes inaccurate. Alternatively, road networks acting as a kind of infrastructure reflect the association of locations. Thus the concentration of road networks indicates the congestion of social-economic activities and municipal facilities to some extent. Based on density analysis of road networks, the area where roads densely distribute is recognized as the central area of a city. Taking Guangzhou City as an example, the road network was studied on a set of spatial scopes, and the central area was delimitated and analyzed. Results showed that the road-density-based delimitation had to be adjusted according to the road system, and the delimitated area was consistent to the real central area to some extent. Since road data is much accessible, road-based method is useful and practical when short of socialeconomic data.

With the rapid development of current earth-observing technology, RS image data storage, management and information publication become a bottle-neck for its appliance and popularization. There are two prominent problems in RS image data storage and management system. First, background server hardly handle the heavy process of great capacity of RS data which stored at different nodes in a distributing environment. A tough burden has put on the background server. Second, there is no unique, standard and rational organization of Multi-sensor RS data for its storage and management. And lots of information is lost or not included at storage. Faced at the above two problems, the paper has put forward a framework for RS image data parallel and distributed management and storage system. This system aims at RS data information system based on parallel background server and a distributed data management system. Aiming at the above two goals, this paper has studied the following key techniques and elicited some revelatory conclusions. The paper has put forward a solid index of "Pyramid, Block, Layer, Epoch" according to the properties of RS image data. With the solid index mechanism, a rational organization for different resolution, different area, different band and different period of Multi-sensor RS image data is completed. In data storage, RS data is not divided into binary large objects to be stored at current relational database system, while it is reconstructed through the above solid index mechanism. A logical image database for the RS image data file is constructed. In system architecture, this paper has set up a framework based on a parallel server of several common computers. Under the framework, the background process is divided into two parts, the common WEB process and parallel process.

With ever-growing archives of multi-source raster images and maps, many spatial applications such as multi-scale database updating, progressive web mapping and 3D terrain visualization call for rapidly automatic integration of GIS and imagery data. The object-oriented methodology display novel characteristics for multi-scale representation. While, management for multi-scale datasets is still lag behind, especially for multi-source data form different spatial reference system (DSRS). In this paper, we review problems with state of the art integration of multisource data. A hierarchical grid framework has been introduced, spatial information multi-grids (SIMG). Three fundamental components to do multi-scale and multi-source datasets analysis are required for SIMG. First, it is necessary to fastly unify different spatial reference system (DSRS) data. Secondly, efficient spatial grid and scale encoding must be applied to support flexible management of multi-scale datasets. Moreover, strategy delineated image data simplification from detailed to broad scale must to be developed. The approaches including the optimal scale identification, object-oriented upscaling and spatial grid and scale encoding for image-objects have been presented. And the experimental was implemented by applying the framework to integrate vector map of SRS in Beijing54 with Landsat TM image of SRS in WGS84, to detect city region sprawl in Zhengzhou located by the Yellow river, China. It is suggested by results that real-time DSRS integration need fewer time cost than traditional method. The image classification accuracy at optimal scale reached 90.4 percent of kappa, and upscaling results of multi-scale datasets here were more outstanding than multilevel wavelets method. So, this study was easily operated with great effectiveness.

The data-intensive and computation-intensive characteristics of the geo-processing require scalable, flexible, and distributed geo-computing platforms. We employ P2P and Grid technologies to construct a prototype of P2P-Grid GIS, which can integrate distributed spatial data and computing resources to accomplish complex and large-scale spatial processing tasks. The JXTA is a general P2P toolkit originally used in our system. It has many modules and functionalities unnecessary for the prototype, which prove to decrease the system performance. Therefore, we design our own P2P communication scheme called CoreP2P. In this paper, we firstly give a brief description of the architecture of P2P-Grid GIS. We also identify the group communication requirements in the P2P-Grid GIS, which include spatial data transfer and control message transmission. Then, we discuss the components of CoreP2P and their respective functionalities in detail. Finally, we build the P2P-Grid GIS based on CoreP2P and compare the performance with JXTA-based system.

Most of the space agencies have built Grid systems to manage large volumes of spatial data archives and products. However, the heterogeneous data structure, the distributed storage location, and the gradual progress of building data service systems, make such spatial grid systems to be grid islands. The broker-based manage model can hide complexity and heterogeneity of spatial data sources, so that the research on broker-based data service is meaningful to promote inter-Grid collaboration for earth observation applications. This paper discusses the special problems of spatial information integration and some features of broker-based data management model. We demonstrate the prototype of building broker-based model to integrate heterogeneous data grid. This work securely provides querying and managing geospatial data and services, and transparent access to the related sources under Grid and Web Service environment. The paper also describe our experiences of case study on seamless integration with Purdue TeraGrid Data by using Storage Resource Broker, which is based on the extensible data service interfaces of China Spatial Information Grid.

In this article, a remote sensing image processing system is established to carry out the significant scientific problem that processing and distributing the mass earth-observed data quantitatively and intelligently with high efficiency under the Condor Environment. This system includes the submitting of the long-distantly task, the Grid middleware in the mass image processing and the quick distribution of the remote-sensing images, etc. A conclusion can be gained from the application of this system based on Grid environment. It proves to be an effective way to solve the present problem of fast processing, quick distribution and sharing of the mass remote-sensing images.

GridGIS is the application of grid computing technology on GIS field, which aims to realize the spatial information sharing and cooperative service. However, current grid technologies are generally difficult to use, so the development and deployment of Web portals that simplifies usage of grid resources has become popular. Grid-enabled portals can thus serve as simple, single points of entry or gateway to multiple computing resources, providing access to complex grid tools and services. In this paper, we give an overview of GridGIS project and the key role of that GridGIS portal is playing in reaching its goals. Then, we describe the portal and Open Grid Computing Environment (OGCE) portal toolkit. Basing on OGCE and integrated Open Geospatial Consortium (OGC) Web service, we design the architecture of the GridGIS portal. In an open source development environment, we develop and deploy GridGIS portal, which includes authentication module, Grid Port Information Repository (GPIR) portlet, Comprehensive File Management (CFM) portlet, Grid Resource Allocation and Management (GRAM) portlet and Map Viewer portlet.

With the development of remote sensing technological, the data of remote sensing has become even huger, and the process is more complex and time-consuming. This paper presents a decentralized self-coordinating distributed method, designs and implements a decentralized self-coordinating distributed remote sensing image processing prototype system. The principle of this system is to assign remote sensing image processing to other node according to global directory, so as to accelerate the speed of the process. The global directory records all nodes' information including the load balance factor which records the nodes' capability of processing remote sensing image. It provides a new distributed computing model for the remote sensing image processing and gives the remote sensing image processing system flexibility, scalability, higher performance and reliability scale.

The ever-increasing of the large geospatial datasets and the widely application of the complex geocomputation make the parallel processing of GIS an important component of high-performance computing. The paper introduces a two-phase load-balancing scheme for the parallel GIS operations in distributed environment. The paper focus on the parallel framework design and parallel strategy implement of the spatial operations in GIS. Two major aspects of the spatial data partitioning and dynamic load schedule are discussed in detail, declustering the massive data sets into two parts hierarchically: the dynamic share data and the static local data. In the experimental test, we build up the analytical cost model and evaluate the utilize rate of computational power and I/O resource, and analyze the efficiency of the proposed parallel prototype.

Spatial Data Grid is an ideal environment to handle the data-intensive and computing-intensive geo-spatial processes. In this heterogeneous and distributed environment, the requirements of service scheduling are dynamic and diverse. Therefore, an appropriate scheduling mechanism should be adopted, which would be able to deal with the resources properties of a grid environment, such as the data size, network capabilities, and the capabilities of processors, and meet the need of specific GIS (Geographic Information System) applications. This paper proposes a scheduling mechanism based on utility of Quality of Service (QoS). And, this scheduling mechanism, wrapped into a standard WSRF service, provides a transparent way to select the appropriate spatial data service providers in a dynamic spatial data grid and hides the complexity of the scheduling strategy from users to coordinate those required services. Experiments show that our scheduling mechanism can provide services selection and performance guarantees and lead to better spatial resource sharing and significant service performance.

A new distributed computing model of mobile spatial information service is studied based on grid computing environment. Key technologies are presented in the model, including mobile agent (MA) distributed computing, grid computing, spatial data model, location based service (LBS), global positioning system (GPS), code division multiple access (CDMA), transfer control protocol/internet protocol (TCP/IP), and user datagram protocol (UDP). In order to deal with the narrow bandwidth and instability of the wireless internet, distributed organization of tremendous spatial data, limited processing speed and low memory of mobile devices, a new mobile agent based mobile spatial information service grid (MSISG) architecture is further proposed that has good load balance, high processing efficiency, less network communication and thus suitable for mobile distributed computing environment. It can provide applications of spatial information distributed computing and mobile service. The theories and technologies architecture of MSISG are built originally from the base, including spatial information mobile agent model, distributed grid geographic information system (GIS) server model, mobile agent server model and mobile GIS client model. An application system for MSISG is therefore developed authorship by visual c⁺⁺ and embedded visual c⁺⁺. A field test is carried out through this system in Shanghai, and the results show that the proposed model and methods are feasible and adaptable for mobile spatial information service.

Spatial information systems and spatial information in different geographic locations usually belong to different organizations. They are distributed and often heterogeneous and independent from each other. This leads to the fact that many isolated spatial information islands are formed, reducing the efficiency of information utilization. In order to address this issue, we present a method for effective spatial information integration based on web service. The method applies asynchronous invocation of web service and dynamic invocation of web service to implement distributed, parallel execution of web map services. All isolated information islands are connected by the dispatcher of web service and its registration database to form a uniform collaborative system. According to the web service registration database, the dispatcher of web services can dynamically invoke each web map service through an asynchronous delegating mechanism. All of the web map services can be executed at the same time. When each web map service is done, an image will be returned to the dispatcher. After all of the web services are done, all images are transparently overlaid together in the dispatcher. Thus, users can browse and analyze the integrated spatial information. Experiments demonstrate that the utilization rate of spatial information resources is significantly raised thought the proposed method of distributed spatial information integration.

In recent years, the runoff and sand transportation of the Yellow River is declining, the corrosion of shoreline in the Yellow River Delta becomes more and more serious, and this brings up much hidden trouble for the inshore biological environment and engineering facilities. In this article, according to RS and GIS, we analyzed the muti-temporal RS image between 1987 and 2003, abstracted the spatial-temporal information of the shoreline using unsupervised classified method. Built the quantificational-relative model between the runoff and sand transportation and the corrosive area of shoreline based on data from Lijin Hydrology Station and statistical method, and did elementary forecast on the evaluative trend of the shoreline.

It is known that digital elevation models (DEMs) can vary in quality depending on spatial sampling schemes. Three DEMs were created by Kriging interpolation from sampling points which come from different sampling schemes. Using a test setup, three different sampling schemes and different semivariogram models (Circular, Spherical, Tetraspherical, Pentaspherical, Exponential, Gaussian, Rational Quadratic, Hole Effect, K-bessel, J-bessel, and Stable) are compared. The results show uniform random sampling scheme to better than the other candidates.

The extraction of drainage networks and catchment boundaries from digital elevation models (DEMs) has received considerable attention in recent years and is recognized as a viable alternative to traditional surveys and the manual evaluation of topographic maps. Digital data on the position and characteristics of river networks and catchments are important for the analysis of water resources. GIS tools allow for the combined analysis of digital elevation data and environmental parameters in order to derive this kind of information. In this paper we present an application that selecting river network deriving digital elevation data. In this application, we use catchments as the unit of river abstraction. Many researchers took catchments as the base of hydrographic model because the catchments deriving from digital elevation data can reflect the characteristics of terrain which is the foundation of the river network. In the abstraction of river network, how to keep the structure of the river network after abstraction is the very important issue. This is why we choose the catchments deriving from digital elevation models as the unit of our generalization research. Considering the complication of the structure of river network, in this paper, we only choose three drainage patterns which are dendritic drainage patterns, featherlike drainage patterns, and Parallel drainage patterns as the examples of the research. From the results of research, it can not only keep the density of the river network, but also keep the structure of the river network.

Incoming solar radiation is the primary driver for physical and biological process in the earth. Human activities, such as agriculture, forestry, land management, etc, ultimately depend on solar radiation. At a global scale, the geometry of earth's rotation and revolution about the sun cause the gradients of solar radiation. But topography is the major factor modifying the distribution of solar radiation at a landscape scale. Spatial solar radiation models provide a cost-efficient means for understanding the spatial variation of solar radiation over landscape scales. Geographic Information system (GIS) has become established tools for analyzing such models. Among such models, the Solar Analyst draws from the strengths of both point-specific and area-based models. It can calculate solar radiation integrated for any time period. In this paper, this model was used to estimate the spatial distribution of incoming potential solar radiation in Xinjiang, China. The 1km resolution digital elevation model (DEM) derived from 1:250000-scale topographic maps and other topographic factors (altitude, slope, aspect, etc derived from DEM) of Xinjiang were used as the basis for generating digital maps of the important parameter required to run Solar Analyst model. With the assistant of topographic factors and Solar Analyst model, the spatial distribution of monthly incoming potential solar radiation with 1km resolution was estimated. Actual solar radiation data were obtained from 13 meteorological stations for the result validation. Validation determined that the mean relative error (MRE) of incoming potential solar radiation ranges from 3.8% in Jul to 12.2% in Dec and the mean value of monthly MRE is 7.1%. The MRE is larger in winter than in other season. In conclusion, the simulated results of model are basically up to the level of application requirement. The Solar Analyst model may serves as a good tool for estimating spatial patters of monthly incoming potential solar radiation in Xinjiang. Application of Solar Analyst in Xinjiang and analysis of the spatial distribution characteristics of monthly incoming potential solar radiation have great significance for the research fields of agriculture, forestry and ecology in Xinjiang, China.

Channel junctions are the intersection points of different gullies in a drainage area. Base on DEM data and GIS process, an effective extraction method of channel junctions is proposed at first in this paper. Then with the definition of channel junction density being introduced, the rationality and validity that it is used to describe erosion intensity at macro-scale is explored. Meanwhile, the quantitative difference of channel junction density in the Loess Plateau in North Shaanxi Province of China is analyzed. The experiment results show that there is a strong correlation of channel junction density and gully density. Moreover, channel junction density keeps more sensitive than gully density when proper threshold values are applied at different grid resolution scales. In addition, channel junction density and the loess landform types correlate intensively, which reveals the great potential significance of channel junctions on geomorphology research. At the same time, the variations of channel junction density at different order levels in the typical watersheds are discussed. So, the research is hopeful in deepening our understanding on landform characteristics and evolutions of the Loess Plateau.

Contour fitting based on moving surface is a common algorithm in map digitalization. But due to the limitation of the elevation fitting models, the elevation of grid points in the DEM may comprise systematic errors, and it is unavoidable to cause the local distortion of the generated contour. In this paper, sample dispersion factor was introduced to the elevation fitting model for the grid point in the DEM, which was related to both the number of the sampled points in the selected area around the fitting point and the distances between the sampled points. The influence of sample dispersion factor was analyzed comprehensively, and the rule for optimally selecting points was discussed. Furthermore, the steps to fit contours considering the sample dispersion factor were suggested. With simulated data collected from a standardized digital map, the precision of the generated contour considering sample dispersion factor was analyzed in detail and some beneficial conclusions were made.

In this paper, pixel based matching methods, and the fact that registering accuracy of phase values, for their direct function in DEM extraction, has more impact on DEM results are discussed. Then the authors analyzed the disadvantages of traditional phase average gradient function method, which can be concluded as human interference required and its sensitivity to noises inducing low accuracy. To get avoid of those shortcomings, a modified phase average gradient function method was proposed in which the theory of pyramid matching was also brought in to make sure of reliability and lessen the amount of computation. Experiments are carried out and results, in the form of coherence maps, of the new method were compared with that of accuracy testified largest correlation coefficient method in existed software. And the conclusion that it can gain better results was drawn. At last, further developments that can be made in the future were discussed.

Slope spectrum is a statistic model of slope distribution in a certain area. Previous researches display a potential importance of the slope spectrum in geomorphological studies. To quantitatively depict the slope spectrum, three indices (H, T_d, S) were proposed, which can appropriately depict quantity features of slope distribution, but are difficult in depicting spatial structure of slope distribution. Hence, this paper suggests slope-landscape TUPU to quantitatively depict the spatial structure of slope distribution. The slope-landscape TUPU take each test area as an independent landscape unit, and the slope class as patches constituting the landscape. So, theory and methodology of landscape ecology are applied to describe the spatial structure of slope distribution directly. Results show that the slope-landscape TUPU is capable of depicting spatial structure of slope spectrum. A continuous changes of the slope-landscape TUPU from south to north of the Loess Plateau shows an obvious spatial variation of surface roughness in the area, which is proved to be of great significance in describing the surface roughness. This research also suggests relationship between digital terrain analysis and landscape ecology.

A new elevation points sampling method, namely TIN-based Sampling Method (TSM) and a new visual method called Elevation Addition Method (EAM), are put forth for representing the typical terraces in Shanxi loess plateau area. The DEM Feature Points and Lines Classification (DEPLC) put forth by the authors in 2007 is perfected for depicting the main path in the study area. The EAM is used to visualize the terraces and the path in the study area. 406 key elevation points and 15 feature constrained lines sampled by this method are used to construct CD-TINs which can depict the terraces and path correctly and effectively. Our case study shows that the new sampling method called TSM is reasonable and feasible. The complicated micro-terrains like terraces and path can be represented with high resolution and high efficiency successfully by use of the perfected DEPLC, TSM and CD-TINs. And both the terraces and the main path are visualized very well by use of EAM even when the terrace height is not more than 1m.

For the last decades, GIS software technologies have made tremendous development and applied to many special fields when their targets are relevant to geographical locations. But the basis of cartographic mapping of GIS is a restriction for more development in GIS data modelling, storage and manipulation. Recently, much attention is being paid on ORDBMS(Object Relational Database Management System) to represent and manage GIS Data. New approaches have earned acceptance in many research communities and several proposals have emerged in commercial software for solving the management and manipulation on GIS vector data. Though the storage and management of field-based model data(e.g. raster, DEM, TIN) have got less achievement and people still use files and procedural ways to manipulation field-based GIS data in common applications. In this paper a new structure model using ORDBMS technology for field-based data's storage and management was proposed on the basis of full discussion on several GIS data management technologies, then a problem-oriented approach for DEM data management and manipulation was designed and implemented through open source software systems PostgreSQL and Python language. Experimental examples of different DEM data souces were stored, managed and used by using the extended spatial database system. The experiments illustrated that this solution would be a useful supplement to spatial database and it provided an effective way to DEM data management and analysis, and support the interoperability between vector data and field data.

Contour line is a closed curve that joined by points of the same elevation. This paper puts forward a new algorithm of creating contour line based on DEM, which uses the method of tracking the same elevation point to study the algorithm based on regular grid. This paper will be divided the algorithm of creating contour line into four sub-algorithms, namely: the algorithm of elevation comparison; the algorithm of calculating the same elevation point coordinates; the algorithm of tracking next point of the same elevation, the algorithm of tracking contour line. The algorithm of elevation comparison is mainly used in judging whether a contour line with appointed elevation passes through a side of the grid; the algorithm of calculating the same elevation point coordinates is used to calculate coordinates of contour lines across the grid's side; function of the algorithm of tracking next point of the same elevation is to track next point of the same elevation by following the trend of contour lines; the algorithm of tracking contour line aims in tracking coordinates of the point which has the equal value of elevation with the point in row x and column y.

How to choose contour interval in different geomorphologic type areas is a challenging job. In the paper a statistical texture method is used to measure the distance between Loess Hillock and Loess Ridge in Loess Plateau, which geomorphologic types are hills. The result shows that when the two areas classified into 25 classes or so with the contour interval 15 and 19 individually, the class separability seems more distinct than less than 25 classes. The results also shows that when the number of class is bigger than 25, the class separability decrease instead of increasing correspondingly. It seems that the too many classes used may produce more details in cost of decreasing class separability. And in the seven statistical variables, the number of polygons is the most stable while the mean grayscale, the standard variation of grayscale are the most sensitive when the contour interval changes. The result indicates that the contour interval mainly influences by elevation and relative relief without more information which being dominant. By aid of an appropriate contour interval, the landform features can be easily extracted and is very helpful in delaminate the topography.

This paper discusses the theory and technology of the digital color relief shading mapping, and the theory and method for the digital relief shading. The paper introduces basic method of designing digital color relief shading, and discusses key technology of digital color relief shading, and provides scientific approaches of mapping relief shading based on DEM.