Remote sensing describes the instruments and techniques used to observe the earth from a distance. These include the satellites and their sensors, the computer systems used to process images, and the techniques scientists and researchers employ to interpret the images.

There is a wide variety of applications for remote sensing. Scientists use satellites to track weather systems and forest fires. Military services utilize remote sensing to define objectives and provide air and ground forces with information. Commercial companies operate satellites that provide high-resolution maps and geographic information.

With this advanced technology, it is now possible to observe the entire globe, scan hemispheres, or examine minute details. Satellites such as Terra and Landsat record large expanses. Others, including QuickBird, IKONOS, and OrbView satellites, capture incredible detail over small areas.