Spatial analysis is all about understanding and measuring the extent to which phenomena are allocated across space. People, businesses and the like never locate themselves randomly in space. Quantifying the underlying spatial process is the first step to prescribing more efficient and effective strategies for resource allocation.
Here is an example of how spatial analysis can be used to understand an underlying spatial process – Why do certain retail stores cluster together? For a slightly more statistical take on spatial analysis, check out this piece on visualizing neighborhood change.