Weighted coordinates transformation method for map overlay with non-homogeneous space partition

Map overlay is one of the most frequent tasks for research and practical application in fields such as urban planning, surveying, remote sensing, and GIS. Although affine transformation or the Helmert transformation currently used in commercial CAD or GIS software can satisfy some needs of map overlay, inaccurate overlay of the control points remains to be resolved. In this paper, we propose a weighted coordinates transformation method for map overlay, which is subject to the non-homogeneous nature of maps, to overcome the deficiency of traditional transformation methods. The weighted method utilizes Delaunay triangulation to partition a map into a set of triangles or a TIN as the basis for coordinates transformation. The test result shows that the proposed method does achieve an exact overlay of all control points and also performs better for non-control points than an affine transformation. (C) 2003 Elsevier Ltd. All rights reserved.