Abstract:
Remote sensing, encompassing the study of satellite data, is a powerful technique for exploration, mapping and management of the earth resources. It is understood to imply the acquisition of information about and object by scientific devices called sensors without being any physical contact between the object and the sensing device.
The basic principle involved in remote sensing is each object, depending upon its physical characteristics, reflects, emits and absorbs varying intensities of radiation at different EM wavelength ranges. Using information from one or more wavelength ranges, it is possible to discriminate between different types of ground objects (e.g. water, dry soil, wet soil, vegetation, rocks etc.) and map their distribution on the ground. One of the important remote sensing technique use is aerial photography, Aerial photography has essential remained to the visible part of the electromagnet spectrum where it is only a very fraction of the electromagnetic spectrum. Remote sensing techniques have extended the scope of utilisation of the electromagnetic spectrum to almost its entire range.
The electromagnetic radiation (EM) is the source of all signals collected by most remote sensing instruments. The source of this energy varies depending on the sensor characteristics. Most systems rely on the sun to generate all the EM energy needed to image their own energy, called active sensors, transmits that energy in a certain direction and records the portion reflected back to features within the single path.
