December 6, 2004
The ancient city of Jerusalem is cloaked in shades of purple in this image based on data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite on April 3, 2000. Using shortwave infrared, infrared, and red wavelengths (ASTER bands 4, 3, and 2) in the traditional red, green, and blue channels of the image creates this false-color version of the city in which developed areas are purple, vegetation is green, water is deep blue or black, and naturally bare (or thinly vegetated) ground is pinkish-brown. Just to the right of the center of the scene is the downtown area, which appears a brighter purple than the surrounding parts of the city, perhaps because it is more densely developed or the materials or types of structures in that part of the city are different. At the southern edge of the area, a bright green spot shows the location of the Ha-Atsma'ut Garden.
Topics: Radiometry, Geographic information systems, Electromagnetic radiation, False-color, Thermal infrared spectroscopy, Advanced Spaceborne Thermal Emission and Reflection Radiometer, Color, Radiometer, Terra, Purple, Infrared, Electromagnetic spectrum, Advanced Spaceborne Thermal Emission, Jerusalem, Reflection Radiometer, National Aeronautics and Space Administration