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Data can be used for coastal mapping and erosion prevention. Ocean applications: Monitor ocean circulation and current systems, measure ocean temperature and wave heights, and track sea ice. Data can be used to better understand the oceans and how to best manage ocean resources. Hazard assessment: Track hurricanes, earthquakes, erosion, and flooding. Data can be used to assess the impacts of a natural disaster and create preparedness strategies to be used before and after a hazardous event.
In this Landsat false-color images, forest appears as bright red interspersed with patches of logging. Snow appears white, and ash is gray. All of the cabins were damaged and one pavilion is gone altogether. The area is now inaccessible due to the cut from the harbor to the cabins. These cuts were likely formed when surge flowed over the island from the sound side. The dunes in front of the. Skip to main content. Search Search. Mapping, Remote Sensing, and Geospatial Data.
Some examples are: Cameras on satellites and airplanes take images of large areas on the Earth's surface, allowing us to see much more than we can see when standing on the ground.
Sonar systems on ships can be used to create images of the ocean floor without needing to travel to the bottom of the ocean. Cameras on satellites can be used to make images of temperature changes in the oceans. Some specific uses of remotely sensed images of the Earth include: Large forest fires can be mapped from space, allowing rangers to see a much larger area than from the ground.
Tracking clouds to help predict the weather or watching erupting volcanoes, and help watching for dust storms. Tracking the growth of a city and changes in farmland or forests over several years or decades. Discovery and mapping of the rugged topography of the ocean floor e. Apply Filter. What are the band designations for the Landsat satellites? The sensors aboard each of the Landsat satellites were designed to acquire data in different ranges of frequencies along the electromagnetic spectrum View Bandpass Wavelengths for all Landsat Sensors.
What are the acquisition schedules for the Landsat satellites? The Landsat 7 and Landsat 8 satellites orbit the Earth at an altitude of kilometers miles in a kilometer mile swath, moving from north to south over the sunlit side of the Earth in a sun synchronous orbit, following the World Reference System WRS Active sensors use internal stimuli to collect data, emitting energy in order to scan objects and areas whereupon a sensor measures the energy reflected from the target.
RADAR and LiDAR are typical active remote sensing tools that measure the time delay between emission and return in order to establish the location, direction, and speed of an object. The remote sensing data gathered is then processed and analyzed with remote sensing hardware and computer software, which is available in a variety of proprietary and open source applications.
Remote sensing technology is used in a wide variety of disciplines in thousands of different use cases, including most earth sciences, such as meteorology, geology, hydrology, ecology, oceanography, glaciology, geography, and in land surveying, as well as applications in military, intelligence, commercial, economic, planning, and humanitarian fields.
Some typical remote sensing examples include:. Remote sensing makes it possible to collect data from dangerous or inaccessible areas, with growing relevance in modern society. It replaces slower, costly data collection on the ground, providing fast and repetitive coverage of extremely large areas for everyday applications, ranging from weather forecasts to reports on natural disasters or climate change.
Remote sensing is also an unobstructive method, allowing users to collect data and perform data processing and GIS analysis offsite without disturbing the target area or object. There are three primary types of orbits in which satellites reside: polar; non-polar, low-Earth orbit, and geostationary.
Polar-orbiting satellites are in an orbital plane that is inclined at nearly 90 degrees to the equatorial plane. This inclination allows the satellite to sense the entire globe, including the polar regions, providing observations of locations that are difficult to reach via the ground.
Many polar-orbiting satellites are considered sun-synchronous, meaning that the satellite passes over the same location at the same solar time each cycle. Polar orbits can be ascending or descending.
In ascending orbits, satellites are moving south to north when their path crosses the equator. In descending orbits, satellites are moving north to south. These orbits do not provide global coverage but instead cover only a partial range of latitudes. The Global Precipitation Measurement GPM mission is an example of a non-polar, low-Earth orbit satellite covering from 65 degrees north to 65 degrees south.
These satellites capture the same view of Earth with each observation and so provide almost continuous coverage of one area. Electromagnetic energy, produced by the vibration of charged particles, travels in the form of waves through the atmosphere and the vacuum of space. These waves have different wavelengths the distance from wave crest to wave crest and frequencies; a shorter wavelength means a higher frequency.
Some, like radio, microwave, and infrared waves, have a longer wavelength, while others, such as ultraviolet, x-rays, and gamma rays, have a much shorter wavelength. Visible light sits in the middle of that range of long to shortwave radiation.
This small portion of energy is all that the human eye is able to detect. Instrumentation is needed to detect all other forms of electromagnetic energy. NASA instrumentation utilizes the full range of the spectrum to explore and understand processes occurring here on Earth and on other planetary bodies. Some waves are absorbed or reflected by elements in the atmosphere, like water vapor and carbon dioxide, while some wavelengths allow for unimpeded movement through the atmosphere; visible light has wavelengths that can be transmitted through the atmosphere.
Microwave energy has wavelengths that can pass through clouds; many of our weather and communication satellites take advantage of this. Spectral signatures of different Earth features within the visible light spectrum. Credit: Jeannie Allen. All things on Earth reflect, absorb, or transmit energy, the amount of which varies by wavelength. Researchers can use this information to identify different Earth features, as well as different rock and mineral types.
The number of spectral bands detected by a given instrument, its spectral resolution , determines how much differentiation a researcher can identify between materials. Just as iron and copper look different in visible light, iron- and copper-rich minerals reflect varying amounts of light in the infrared spectrum. This graph compares the reflectance of hematite an iron ore with malachite and chrysocolla copper-rich minerals from to 3, nanometers.
Sensors, or instruments, aboard satellites and aircraft use the Sun as a source of illumination or provide their own source of illumination, measuring the energy that is reflected back. Sensors that use natural energy from the Sun are called passive sensors; those that provide their own source of energy are called active sensors.
Diagram of a passive sensor versus an active sensor. Note that most passive sensors cannot penetrate dense cloud cover and thus have limitations observing areas like the tropics where dense cloud cover is frequent. Active sensors include different types of radio detection and ranging radar sensors, altimeters, and scatterometers.
The majority of active sensors operate in the microwave band of the electromagnetic spectrum, which gives them the ability to penetrate the atmosphere under most conditions.
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