Most GIS's today now incorporate both raster and vector functions, although each has a primary structure. The choice of data structure really depends on what you're analyzing and the spatial resolution you require. Polygonal areas or regions are defined by closed sets of bounding vertices or clusters of cells. In practice, most GIS work today is really just computer-assisted cartography. Major product is hardcopy maps.
People are accustomed to looking at map representations of spatial phenomena.
But hardcopy maps are static and dimensionally somewhat restricted, where GIS is dynamic and dimensionally unrestricted. GIS does need selling, because it is so expensive . Appropriate levels of investment in infant GIS technologies are hard to determine. Facing budget cutbacks, GIS may be first to go. The analytical sophistication of users, not the operational capabilities of the GIS, is the major bottleneck in the diffusion of GIS technologies.