Using a Fuzzy Surface-based Cartographic Representation to Decrease Digitizing Efforts for Natural Phenomena

On a previously-digitized map, a series of 685 points were screen-digitized so as to represent major spatial features of each polygon composing 17 forest types having inherently uncertain boundaries; three forest types having precise boundaries were treated as such. From these points and three exact types, surfaces were generated which provided weights of the certainty of having each of the 20 forest types at a location. These surfaces were “reconstituted” into a thematic map by assigning each location to the type having the highest weight. When compared to the precisely digitized and rasterized map, area1 and locational inaccuracy were 5% and 18%, respectively, for the reconstituted thematic map. For certain situations-such as the preparation of long-term forest management plans-these results show promise for adequately representing maps of natural features while reducing digitizing efforts. Kim Lowell and Christopher Gold