![]() ![]() Ultrasound (acoustic) and radar tide gauges measure sea level, tides and wave direction in coastal and offshore tide gauges.By measuring the height and wavelength of ocean waves, the altimeters measure wind speeds and direction, and surface ocean currents and directions. By measuring the bulges of water caused by gravity, they map features on the seafloor to a resolution of a mile or so. Laser and radar altimeters on satellites have provided a wide range of data.Interferometric synthetic aperture radar is used to produce precise digital elevation models of large scale terrain (See RADARSAT, TerraSAR-X, Magellan). Other types of active collection includes plasmas in the ionosphere. Doppler radar is used by local law enforcements' monitoring of speed limits and in enhanced meteorological collection such as wind speed and direction within weather systems in addition to precipitation location and intensity. Conventional radar is mostly associated with aerial traffic control, early warning, and certain large-scale meteorological data.For a summary of major remote sensing satellite systems see the overview table.įurther information: Remote sensing (geology) and Remote sensing in archaeology The basis for multispectral collection and analysis is that of examined areas or objects that reflect or emit radiation that stand out from surrounding areas. Other uses include different areas of the earth sciences such as natural resource management, agricultural fields such as land usage and conservation, greenhouse gas monitoring, oil spill detection and monitoring, and national security and overhead, ground-based and stand-off collection on border areas. Orbital platforms collect and transmit data from different parts of the electromagnetic spectrum, which in conjunction with larger scale aerial or ground-based sensing and analysis, provides researchers with enough information to monitor trends such as El Niño and other natural long and short term phenomena. ![]() Remote sensing also replaces costly and slow data collection on the ground, ensuring in the process that areas or objects are not disturbed. Military collection during the Cold War made use of stand-off collection of data about dangerous border areas. Remote sensing applications include monitoring deforestation in areas such as the Amazon Basin, glacial features in Arctic and Antarctic regions, and depth sounding of coastal and ocean depths. Remote sensing makes it possible to collect data of dangerous or inaccessible areas. RADAR and LiDAR are examples of active remote sensing where the time delay between emission and return is measured, establishing the location, speed and direction of an object. Active collection, on the other hand, emits energy in order to scan objects and areas whereupon a sensor then detects and measures the radiation that is reflected or backscattered from the target. Examples of passive remote sensors include film photography, infrared, charge-coupled devices, and radiometers. Reflected sunlight is the most common source of radiation measured by passive sensors. Passive sensors gather radiation that is emitted or reflected by the object or surrounding areas. Remote sensing can be divided into two types of methods: Passive remote sensing and Active remote sensing. Overview This video is about how Landsat was used to identify areas of conservation in the Democratic Republic of the Congo, and how it was used to help map an area called MLW in the north. It may be split into "active" remote sensing (when a signal is emitted by a satellite or aircraft to the object and its reflection detected by the sensor) and "passive" remote sensing (when the reflection of sunlight is detected by the sensor). ![]() It includes the surface and the atmosphere and oceans, based on propagated signals (e.g. In current usage, the term remote sensing generally refers to the use of satellite- or aircraft-based sensor technologies to detect and classify objects on Earth. exploration geophysics, hydrology, ecology, meteorology, oceanography, glaciology, geology) it also has military, intelligence, commercial, economic, planning, and humanitarian applications, among others. Remote sensing is used in numerous fields, including geophysics, geography, land surveying and most Earth science disciplines (e.g. The term is applied especially to acquiring information about Earth and other planets. Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. Synthetic aperture radar image of Death Valley colored using polarimetry For other uses, see Remote sensing (disambiguation). ![]()
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