Chapter 17 - Remote sensing and geographic information system for soil analysis—vulnerability mapping and assessment

Abstract

The science of remote sensing involves collecting information about objects or locations from a great distance, usually with the use of aircraft or satellites. Remote sensors detect energy reflected from the ground to gather data. These sensors may be mounted on satellites or aboard aircraft. Both passive and active remote sensors are used. Sensors that are passive react to outside stimuli. They keep track of the energy that the Earth’s surface naturally reflects or emits. Reflected sunlight is the most frequent radiation source that passive sensors can detect. Active sensors, in contrast, gather information about the Earth by responding to internal stimuli. The length of time it takes for a laser to reflect back to a sensor, for instance, is measured by a laser beam remote sensing system that projects a laser at the Earth’s surface.