Geographic information systems uses spatial analysis in order to understand geographic questions. Related: Basic uses of GIS
Area cartogram maps are maps of non-absolute space where the areal extent is in proportion to some measured value. More: Area Cartograms Explored.
Buffering in GIS creates a polygon layer that extends out or in from a set distance from a point, line, or polygon. More: Buffers in GIS, Buffering Tool for ArcGIS.
Clip analysis is the function of using the extent of one geographic layer to clip the extent of another geographic layer. More: Clip Analysis using ArcGIS Desktop.
Distance decay is a phenomenon observed between locations or ethnic groups- the further apart they are, the less likely it is that they will interact very much. More: Distance Decay.
Heat mapping, from a geographic perspective, is a method of showing the geographic clustering of a phenomenon. More: Heat maps in GIS.
Line of Sight and Visibility Analysis
Light of sight measures the unimpeded view or access from one point to another point across a terrain or surface. Visibility analysis is the end result, a line color coded to show which segments are visible and which segments have an obstructed view. More: Light of Sight.