Pattern Recognition and Typification of Ditches

This paper will present the algorithms developed for the generalization of ditches in the CARGEN project. Despite the increasing number of algorithms available for cartographic generalization, only few of them address directly the problem of typification; noticeably this has been done in the context of building and road network generalization only. Ditches are man made features used to carry water, they are commonly found in groups in rural environments and in maps they are widely used to describe such a landscape. Groups of ditches usually show a regular pattern of straight lines, hence they lend themselves to be generalized through typification. In this paper a novel algorithm for the typification of ditches will be explained. The algorithm has been developed inside the Italian CARGEN project, aiming at the automatic generalization of 1:25000 data from 1:5000 data. The first section introduces typification, followed by brief review of related work in section two; the third section gives a description of the salient features of ditches; all the consideration of section one and three will be then used to set up a generalization algorithm that is explained in section four. Section five illustrates the results and gives a perspective on the future work.