Click on the image to the right to view three Landsat Thematic Mapper (TM) images
of the area near Washington Dulles International Airport. On the left is an image acquired November 1982, the center is from October 1989
and the image on the right is from October 1997. Multispectral images such as these allow for various
wavelegths of light to be assigned to different colors. In this image, red indicates high
infrared reflectance and blue indicates high visible wavelength reflectance. Because
vegetation reflects most strongly in the infrared, it appears red. Developed or urbanized
areas reflect more light in visible wavelengths and therefore appear
blueish in these images.
The location of Dulles Airport has had an important effect on the economic development of the area. In the satellite images, notice the increase in urbanized areas to the east and north of the airport in the years 1982-1997.