ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
Fig. 4 The final result after modification 
4. Experimental Results 
Fig.3 shows an example of non-linear transform of cadastral map. 
Fig.3 (a) is the original cadastral map that is roughly correct in 
shape and topology, but doest confirm with the real world in 
position (the coordinates of each vertex and the origin of text). 
Fig.3 (b) is the result of non-linear transformation with collinear 
constrain. It is have been confirmed that collinear line groups, 
terminal points, arc and text strings (their origins) has been 
correctly transformed. 
Fig.4 shows the final modification result in accordance to the real 
world coordinates, which is obtained from topographic maps. 
5. Discussions and Future Works 
Since the proposed algorithm of non-linear transformation cannot 
guarantee 100% correct rectification results unless 
corresponding points with enough density are specified, manual 
modification will be necessary. Furthermore, the position of 
boundary usually do not confirm with the actual one. Therefore, 
adjustment of boundaries according to the position of road edge, 
walls, plantation boundary etc. is necessary. The research by 
Chen [3] enables partial automation of such process. 
Currently, the corresponding points between cadastral map and 
cartographic map are performed manually. Since the cadastral 
line segment of roads has very high similarity to the road lines in 
cartography, we are going to develop algorithms for automatic 
matching of such kind of corresponding points 
Reference 
1. T. Kondo, X. Chen, W. Lu and T. Doihara: A hybrid system for 
map digitization. Proceedings of 2rd International Workshop on 
Dynamic and Multi-dimensional GIS, pp. 31-34, 1999, China 
2. Jonathan Richard Shewchuk: A Two Dimensional Quality Mesh 
Generator and Delaunay Triangulator. 
(http://www.cs.cmu.edu/~quake/triangle. html) 
3. X. Chen, J. Du, T. Doihara, W. Lu: Graphics Matching Based 
Old Cadastral Map Generalization. Proceedings of 
Geolnformatics'2000, USA