Mapping is important to science, because it allows scientists working in the field to position themselves with respect to their surroundings, to understand the context of their observations, and to integrate their observations with other kinds of data about the same locations. In other words, mapping provides the framework for many different kinds of science. Mapping from space is important for scientists working in poorly mapped areas such as the Amazon Basin or Antarctica, and in areas like Alaska where precise mapping is not generally available. Indeed, if we include images from airborne as well as satellite sensors then all maps produced operationally by the U.S. Government since 1957 have been based on remote sensing. This joint effort by NASA, NIMA, the USGS, Germany, and Italy will provide a substantial upgrading in the quality of basic data on the elevations of a large portion of the planet's surface.
Monitoring is essential for the detection of change on the Earth's surface.
Geophysicists use remote sensing to detect small movements in the Earth's crust. Urban and regional planners use remote sensing to detect and monitor urban growth. Researchers in ecology and forestry use remote sensing to provide the base data for habitat characterization, and to detect the changes that result from urbanization and the clearing of forest for agriculture. In many of these examples remote sensing is the only available source of information. Mapping from the ground using traditional methods is expensive, especially when areas must be remapped frequently to monitor change.