Spatial data analysis constitutes a very wide range of visual, theoretical, qualitative, statistical, cartographic, and data manipulation procedures. Spatial statistics are one subset of this range of analytical approaches. In a GIS environment, spatial statistics are software-based tools, methods, and techniques for describing and modeling spatial distributions, patterns, processes, and relationships. While some spatial statistical methods are based on similar concepts and may even share similar goals with traditional, nonspatial statistical methods, spatial statistics are unique in that they constitute a set of tools developed specifically for use with geographic data. Unlike traditional [Page 437]statistical methods, spatial statistics incorporate space—area, length, proximity, orientation, and/or spatial relationships—directly into their mathematics.