This metadata for the Urban Interface was taken from the GeoMAC web site map.

The Urban Interface comes from the Nighttime Lights of the World dataset which contains the first satellite-based global inventory of human settlements, derived from nighttime data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). The DMSP-OLS has the unique capability to observe faint sourcesof visible-near infrared emissions present at the Earth's surface, including cities, towns, villages, gas flares,and fires. National Geophysical Data Center (NGDC) has developed algorithms for producing georeferenced fire and nighttime lights products.