With over half of the world’s population now residing in urban areas, the human footprint is visible through a network of settlements. Cities, towns, and villages are connected by settlements dotting along rivers and road networks. Researchers at the German Remote Sensing Data Center (DFD) have created a deceptively simple black and white visualization using data acquired by the German radar satellites TerraSAR-X and TanDEM-X.
The globe showing the Global Urban Footprint (GUF) was developed by Urban Footprint Processor (UFP). The three-step process involves extracting, classifying, and mosaicking data from 3-meter resolution imagery. Most of the imagery is from 2011 and 2012 with gaps filled in from single scene imagery collected in 2013 and 2014. Thomas Esch from the German Remote Sensing Data Center (DFD) explains, “Radar technology and the fully automated evaluation methodology enable us to record the characteristic vertical structures of settled areas, meaning primarily the buildings.” The end result is a global map at 12-meter resolution processed from a total of 180,000 individual images and more than 308 terabytes of data and shows the “urban structures, and hence the proportion of settled areas, the regional population distribution and the arrangement of rural and urban areas.”
Visually compare the satellite imagery with the extracted human footprint for the Cologne/Bonn region in Germany by moving the slider back and forth:
View the globe: Global Urban Footprint