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Proceedings Paper

Polarization transformation as an algorithm for automatic generalization and quality assessment
Author(s): Haizhong Qian; Liqiu Meng
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Paper Abstract

Since decades it has been a dream of cartographers to computationally mimic the generalization processes in human brains for the derivation of various small-scale target maps or databases from a large-scale source map or database. This paper addresses in a systematic way the polarization transformation (PT) - a new algorithm that serves both the purpose of automatic generalization of discrete features and the quality assurance. By means of PT, two dimensional point clusters or line networks in the Cartesian system can be transformed into a polar coordinate system, which then can be unfolded as a single spectrum line r = f(α), where r and a stand for the polar radius and the polar angle respectively. After the transformation, the original features will correspond to nodes on the spectrum line delimited between 0° and 360° along the horizontal axis, and between the minimum and maximum polar radius along the vertical axis. Since PT is a lossless transformation, it allows a straighforward analysis and comparison of the original and generalized distributions, thus automatic generalization and quality assurance can be down in this way. Examples illustrate that PT algorithm meets with the requirement of generalization of discrete spatial features and is more scientific.

Paper Details

Date Published: 1 August 2007
PDF: 12 pages
Proc. SPIE 6751, Geoinformatics 2007: Cartographic Theory and Models, 67510Y (1 August 2007); doi: 10.1117/12.759698
Show Author Affiliations
Haizhong Qian, Technical Univ. of Munich (Germany)
Liqiu Meng, Information Engineering Univ. (China)

Published in SPIE Proceedings Vol. 6751:
Geoinformatics 2007: Cartographic Theory and Models
Manchun Li; Jiechen Wang, Editor(s)

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