The Night Earth map shows the lights that are visible at night on the Earth's surface.
The brightest areas of the Earth are the most urbanized, but not necessarily the most populated (compare western Europe with China and India). 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. In Russia, the Trans-Siberian railroad is a thin line stretching from Moscow through the center of Asia to Vladivostok. The Nile River, from the Aswan Dam to the Mediterranean Sea, is another bright thread through an otherwise dark region.
Some regions remain thinly populated and unlit. Antarctica is entirely dark. The interior jungles of Africa and South America are mostly dark. Deserts in Africa, Arabia, Australia, Mongolia, and the United States are poorly lit as well (except along the coast and rivers), along with the boreal forests of Canada and Russia, and the great mountains of the Himalaya.
Two versions of the images are available:
The daylight images provided by Google Maps (maps and satellite views) are also available for reference. The Google Maps API was used for creating the original visualisation.
The 3D map was created using Cesium via OpenLayers and ol3-cesium. This uses imagery from OpenStreetMap, Thunderforest, Bing Maps, and Mapquest.
Geocoding is provided by Google and Nominatim via ol3-geocoder.
As the maps provided by NASA were in a different projection as the one required by Google Maps, the GDAL - Geospatial Data Abstraction Library library was used for the conversion.
While the original image consisted of 87.970 images, the map from 2012 comprises 349.525 images, therefore adding a grand total of 437.495 images for this map.
The detailed images of the cities were taken by astronauts aboard the International Space Station. These have been obtained from the Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth".
Further information can be obtained from the Earth Observatory article Bright Lights, Big City, and NASA's Visible Earth website.
The Aurora Borealis and Aurora Australis (Northern Lights and Southern Lights) data is provided by NOAA - National Oceanic and Atmospheric Administration.
The day/night overlay uses the Google Maps API Addons.
The clouds layer is provided by OpenWeatherMap.
A printed poster with the image above is available for purchase at The Freeman Institute.