Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with it, in contrast to in situ or on-site observation. Remote sensing is used in numerous fields, including geophysics, geography, land surveying, and most Earth science disciplines, such as exploration geophysics, hydrology, ecology, meteorology, oceanography, glaciology, and geology. It also has military, intelligence, commercial, economic, planning, and humanitarian applications, among others. Remote sensing is used to collect data of dangerous or inaccessible areas, and it makes it possible to collect data from extremely large areas for everyday applications, ranging from weather forecasts to reports on natural disasters.
Remote sensing is generally done using satellite- or aircraft-based sensor technologies to detect and classify objects on Earth, including the surface, atmosphere, and oceans, based on propagated signals, such as electromagnetic radiation. Remote sensors can be either passive or active. Passive sensors measure reflected light emitted from the sun, while active sensors use internal stimuli to collect data about Earth, such as a laser-beam remote sensing system that projects a laser onto the surface of Earth and measures the time that it takes for the laser to reflect back to its sensor.
Remote sensing has a wide range of applications in many different fields, including:
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Geography and Earth Science: Remote sensing is used to study the Earths surface, atmosphere, and oceans, and to monitor changes in the environment, such as deforestation, land use, and climate change.
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Military and Intelligence: Remote sensing is used for reconnaissance, surveillance, and intelligence gathering.
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Commercial and Economic: Remote sensing is used for resource exploration, such as oil and gas exploration, and for monitoring crops and other agricultural activities.
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Planning and Humanitarian: Remote sensing is used for urban planning, disaster response, and humanitarian aid.
Overall, remote sensing is an important tool for collecting data about the Earth and other planetary bodies from a distance, enabling data-informed decision making based on the current and future state of our planet.
