Photo Identifiable Ground Control Points

GCP information can be pulled from source imagery like Google Earth and the National Agriculture Imagery Program (NAIP) for control points that have not moved or changed from the base imagery date to your current data set’s date. This type of ground control is referred to as a PIP, or Photo Identifiable Point. Good examples of PIPs are corners of buildings, sidewalks, and roadways. Bad examples of PIPs are trees because they change shape (growth & damage), color (leaf color), and composition (leaf-on or leaf-off).