A core geographic science element of the U.S. Geological Survey's Geographic Analysis and Monitoring (GAM) Program is to monitor land-surface change for the Nation through time.
The Nation's land surface is dynamically evolving and transitioning in response to natural and human processes. The need to understand the transformations and locations where changes are taking place, their underlying causes, and the rate at which the transitions are occurring is fundamental to the health and viability of the Nation's natural and developed environments.