Remote sensing involves the measurement of the specific characteristics of objects or events without being in contact with those objects or events. Traditionally this technique involves using photographs or digital images taken from aircraft or satellites, operated by governmental agencies or private commercial vendors, to survey large areas of the earth's surface.

These surveys may be used to gather information on the extent and effects of large-scale phenomena, such as droughts, floods, deforestation, agricultural practices, urban development, and other terrestrial events. Weather satellite images are perhaps the most familiar example of remote sensing.

Remote sensing has also been used to monitor ocean surface temperatures, ocean surface color resulting from phytoplankton concentrations, ocean surface topography, and coastal shoreline changes. Black-and-white and color aerial photography, combined with groundtruthing, have assisted in mapping shallow coral reef areas. These images have provided information useful in identifying study sites and documenting changes resulting from natural events and human activities.