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Proceedings Paper

Flow paths tracing from raster contours using distance transform
Author(s): Yanlan Wu; Yongqiong Liu; Hai Hu; Chuanyong Yang
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Paper Abstract

Water flow processes operating on the earth's surface play a fundamental role in shaping various landform elements such as stream networks, valleys and watershed boundaries. In the digital environment, surface flow paths have been conventionally derived from a grid-based DEM, where flow directions are assigned based on the direction of steepest descent determined from grid-cell elevations. However, the assigned flow direction pattern often includes problems such as unrealistic direction of flow paths especially in nearly flat areas and depressions. A new method for tracing flow paths is proposed to avoid these problems by two means: 1) Instead of grid-based DEMs, raster contour lines are used as input data; and 2) Not elevation but information derived from the distance transform performed on a contour map is used to assign flow directions. The proposed method has been implemented using the C++ programming language. The results obtained by the new method were compared with those from the existing grid-based methods including the most popular D8 method and its improved algorithms such as Rho8, FD8, FRho8 and DEMON. The new method resulted in better agreement with the original stream networks shown in topographic maps, especially in gentle areas. The use of contour lines makes the new method free from digitizing and interpolation errors, which are often caused in generating a grid DEM from a topographic map. The high availability of contour maps is another advantage of the new method. The method will benefit various hydrological analyses and applications.

Paper Details

Date Published: 16 October 2009
PDF: 10 pages
Proc. SPIE 7492, International Symposium on Spatial Analysis, Spatial-Temporal Data Modeling, and Data Mining, 749255 (16 October 2009); doi: 10.1117/12.838588
Show Author Affiliations
Yanlan Wu, Wuhan Univ. (China)
Yongqiong Liu, Wuhan Univ. (China)
Hai Hu, Wuhan Univ. (China)
Chuanyong Yang, Foshan Urban Planning Design and Surveying Research Institute (China)


Published in SPIE Proceedings Vol. 7492:
International Symposium on Spatial Analysis, Spatial-Temporal Data Modeling, and Data Mining

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