Portland: Correct Lighting, x2 Vertical Exaggeration

These scenes show Portland, Oregon and the countryside around it as seen by the Landsat Thematic Mapper (TM) instrument. Portland sits on the Willamette River south of its confluence with the Columbia River. The city sits very close to several mountains in the Cascade Range, including Mt. Hood, Mt. Adams, and Mt. St. Helens. The terrain of the area is also shown exaggerated by a factor of two to emphasis terrain features such as the mountains and the Columbia Gorge just north of Mt. Hood and south of Mt. Adams.
The shortwave infrared (TM band 5), infrared (TM band 4), and visible green (TM band 2) channels are displayed in the images as red, green, and blue respectively. In this combination, barren and/or recently cultivated land appears red to pink, vegetation appears green, water is dark blue, and artificial structures of concrete and asphalt appear dark gray or black. The natural color images combine TM bands 3, 2, and 1 and map them to red, green, and blue, respectively.

See http://svs.gsfc.nasa.gov/stories/Landsat_USCities/index.html