Practice of deriving information about the earth"s land and water surfaces (target) By employing radiation in one or more regions of the electromagnetic spectrum, reflected or emitted from the earth"s surface (energy and atmosphere) The art, science, and technology of obtaining reliable information about objects and the environment, through the process of recording, measuring and interpreting imagery and digital representation of energy patterns derived from noncontact sensor systems . Primary elements of a remote sensing system: energy source (using own energy = active system, atmosphere (emr is reflected, emitted or backscattered, target, sensor and platform. Ground: receive, pre-process, archive, and disseminate data. User: analyze data: remote sensing scientists develop new generic methods (nasa, applications specialists turn data into information to solve real world problems. Found applications in all fields that require analysis of distributions of natural or human resource on earth"s surface. Common application areas: geology, hydrology, forestry, soil science, urban planning.