City Lights of North America
November 13, 2000
This image of city lights was created with data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Originally designed to view clouds by moonlight, the OLS is also used to map the locations of permanent lights on the Earth’s surface.
The brightest areas of the Earth are the most urbanized, but not necessarily the most populated. Cities tend to grow along coastlines and transportation networks. The United States interstate highway system appears as a lattice connecting the brighter dots of city centers. Scientists such as Marc Imhoff of NASA's Goddard Space Flight Center are using these images to map urban sprawl and study the conversion of farmland to suburbs and the impact it is having on the planet.
(Original image created by Craig Mayhew and Robert Simmon, NASA GSFC, based on DMSP data)