You can also explore false color imagery with Landsat. The site also provides descriptions of common MODIS band combinations. Click on “add layers” and then select one of the alternate band combinations (1-2-1, 3-6-7, or 7-2-1). You can explore the way different band combinations highlight different features by using a browse tool called Worldview, which displays data from many different imagers, including Aqua and Terra MODIS. Images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer ( ASTER) and from the early Landsats are often shown in this band combination because that’s what the instruments measured. In the image below, the water is muddy, and the sediment reflects light. This band combination is valuable for gauging plant health.Ĭities and exposed ground are gray or tan, and clear water is black. The signal from plants is so strong that red dominates the false-color view of Algeria below. Since they reflect more near infrared than green, plant-covered land appears deep red. In this case, plants reflect near infrared and green light, while absorbing red. One of our most frequently published combinations uses near infrared light as red, red light as green, and green light as blue. Thermal infrared, usually shown in tones of gray to illustrate temperature.We use this to differentiate between snow, ice, and clouds. Blue (red), two different shortwave infrared bands (green and blue).Shortwave infrared (red), near infrared (green), and green (blue), often used to show floods or newly burned land.This is a traditional band combination useful in seeing changes in plant health. Near infrared (red), green (blue), red (green).Our four most common false-color band combinations are: Shortwave infrared light highlights the difference between clouds, ice, and snow, all of which are white in visible light. For instance, floods are best viewed in shortwave infrared, near infrared, and green light because muddy water blends with brown land in a natural color image. Though there are many possible combinations of wavelength bands, the Earth Observatory typically selects one of four combinations based on the event or feature we want to illustrate. How to Interpret Common False Color Images Enhancing the subtle differencesīetween the 3 bands of reflected shortwave infrared light used to make this image gives each mineral a Making it possible to map out geology by comparing reflected SWIR light. Each rock type reflects shortwave infrared light differently, The mountains around China’s Piqiang Fault. In the image below, different types of sandstone and limestone make up Active fires, lava flows, and other extremely hot features “glow” in the Newly burned land reflects strongly in SWIR bands, making them valuable for Shortwave-infrared bands are also useful forĭistinguishing between cloud types (water clouds versus ice clouds) and between clouds, snow, and ice, all of This means SWIR measurements can help scientistsĮstimate how much water is present in plants and soil. Soil, the darker the image will appear at these wavelengths. Shortwave infrared light in three regions: 1,400, 1,900, and 2,400 nanometers. Shortwave infrared (SWIR) light includes wavelengths between 1,100 and 3,000 nanometers. These colors are similar to what you would see from an airplane. (A related animation shows how the images were made.) The visible light image shows dark green forest, light green agriculture, brown wetlands, silver urban areas (the city of Miami), and turquoise offshore reefs and shallows. This series of Landsat images of southeastern Florida and the Northern Everglades illustrates why you might want to see the world in false color. (For instance, grass isn’t always green.) Such false-color band combinations reveal unique aspects of the land or sky that might not be visible otherwise. As a result, the colors in the final image may not be what you expect them to be. (For tips on understanding true-color images, read How to Interpret a Satellite Image on the Earth Observatory.")Ī false-color image uses at least one non-visible wavelength, though that band is still represented in red, green, or blue. The result looks like the world as humans see it. Because most visible colors can be created by combining red, green, and blue light, we then combine the red, green, and blue-scale images to get a full-color representation of the world.Ī natural or “true-color” image combines actual measurements of red, green, and blue light. To make a satellite image, we choose three bands and represent each in tones of red, green, or blue.
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