Many applications require some measurement of distance or proximity. For example, a real estate developer would be concerned with the distance between a potential site for a shopping center and an interchange to a major highway.
Proximity analysis determines which pixels of a layer are located at specified distances from pixels in a certain class or classes. A new thematic layer (image file) is created, which is categorized by the distance of each pixel from specified classes of the input layer. This new file then becomes a new layer of the database and provides a buffer zone around the specified class or classes. In further analysis, it may be beneficial to weight other factors, based on whether they fall inside or outside the buffer zone.
The figure below shows a layer containing lakes and streams and the resulting layer after a proximity analysis is run to create a buffer zone around all of the water features.
Use Search (GIS Analysis) function in ERDAS IMAGINE Workspace or Spatial Modeler to perform a proximity analysis. For vector data, use Buffer function in Spatial Modeler.