GMAP Procedure

About Identification Variables

For map data sets and response data sets, id-variables identify the map areas (for example, counties, states, or provinces) that make up the map. A unit area or map area is a group of observations with the same ID value. The GMAP procedure matches the value of the response variables for each map area in the response data set to the corresponding map area in the map data set. It does this in order to create the output graphs.