  Among conceptual innovations, the most important was the distinction between: (a) the data used to draw the polygons forming the boundary of a place (locational information); and (b) the set of features it has, that is, its attributes. Polygons need not have the same size or geometry. When ecological populations and communities are modeled in a GIS framework, explicit asymmetric irregular spatial information can be incorporated without unrealistic simplifying assumptions such as that of representing the spatial structure as a square or some other regular geometric grid. The exploitation of this possibility takes spatially explicit ecological modeling beyond its traditional confines in which the only spatial structures that could be considered are those with regular geometries. Though GIS-based ecological modeling is still in its infancy (and an early example will be discussed in the next paragraph), it is clear that these techniques will allow the construction of spatially-explicit ecological models at a level of detail that was impossible before. Moreover IBMs can now be constructed with such detailed spatial representation. The confluence of IBMs and GIS is arguably the most fecund area of ecological modeling today.