The Prevalence of Objects with Sharp Boundaries in GIS

The debate on vector versus raster based models is nearly as old as the concept of a GIS (Dutton 1979). It was restated as a debate between GIS with an object concept (not to be confused with object-oriented as used in software engineering; (Worboys 1994) uses the term object based GIS, where objects have sharp boundaries delimited by vectors and the GIS which model the continuous variation of attributes over space using a regular tessellation e.g. a raster (Frank 1990). Efforts to merge the two representations were attempted (Peuquet 1983). It has been a very fruitful debate as it has forced us to consider and reconsider the epistemological bases of our work and has led to an extensive discussion of fundamental questions (Chrisman 1987), (Mark and Frank 1991), (Mark 1993). The debate has promoted the development of ever more powerful software, achieving a nearly complete integration of vector and raster data (Herring 1990).