Document Type : Research Paper

Author

• Mahdi Modiri

Associate Professor of Urban planning, Malek-Ashtar University of Technolog

Abstract

Remote sensing is a science that provides valuable information about land objects and phenomena
through distant measurement and without physical contact. As mentioned in the last issue, information can be obtained by measuring and recording changes in electromagnetic fields, gravity and sound waves. Remote sensing is the information that can be exploited by measuring the reflection of electromagnetic waves of the atmosphere and the earth's surface and received by sensors that are installed on the satellites, and after analysis, the necessary information is extracted.
Remote sensors are divided into two main active and passive groups based on source of energy and light. Active sensors such as radar have artificial energy source, and inactive sensors have a natural energy source (the sun) and are similar to cameras and scanners. They act through reflecting information in photographic and digital forms.