Earth's City Lights

This image of Earth's city lights at night shows the spatial distribution, or arrangement, of human settlements. White areas of light show urbanized areas where population is typically large. As you look at the image, you can see the pattern of this distribution. Cities are along coastlines and transportation networks.

The image was created with data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). The OLS sensor orbits Earth, acquiring one swath, or area, of data at a time. The swaths are processed to find non-cloudy picture elements, or pixels. Over the course of a year, all non-cloudy pixels for a particular location on Earth are averaged to produce a global grayscale image. The color image you see in this image is created by combining the grayscale DMSP image with a version of the Blue Marble: Next Generation (BMNG) image that is modified to appear more "night-like."