3D CARTOGRAPHIC AGGREGATION USING FUZZY THEORY APPROACH

J. Raheja, S. Ragunath

CEERI, Pilani, India

jagdish@ceeri.ernet.in

In every map, irrespective of its theme, objects are represented at a reduced scale. As the map contents do not decrease proportionally in the direct ratio to the reduction of the map size, an increasing density of the map contents occurs at smaller scales. That is where the generalization plays an important role. Major operations of generalization include simplification, aggregation, typification, displacement, enhancement and symbolization.

Among these generalization operations, a

ggregation groups a selected set of similar entities to form one entity over the original footprint. An aggregation algorithm, based on various rules and constraints in 3D domain, is used to form this new object. However, these set of rules and constraints have been studied earlier and are crisp in nature resulting in poor aggregation. In this paper, Fuzzy logic approach has been used which applies these rules to drive aggregation. Fuzzy theory, which always tend to mimic the behavior of human, work the same way as human think. However, the decision and the means of choosing that decision are replaced by fuzzy sets and the rules are replaced by fuzzy rules. It is shown in this paper that fuzzy based rules results in more natural aggregation as compared to crisp rule based approach. A fuzzy aggregation simulator (FAS) has been developed based upon fuzzy rules to augment the comparison.