Urban areas represent one of the most important forms of land cover/use and the changes associated with their expansion are also some of the most important forms of land cover/use change. While urban areas still represent today a small proportion of the Earth’s land surface, their impacts on hydrology, weather, resource demand and utilization, and emissions, are felt from local to regional to continental, and even global, scales. In addition, more than half of the world’s population currently resides in urban areas. The ability to accurately map and monitor urban areas is thus critical to a better understanding of these impacts as well as the potential impacts on their residents.
Characterizing the physical properties of urban land cover from satellite remote sensing makes it possible to map the form and spatial extent of urban land cover/use and to quantify changes in their form and extent. This provides objective, physically-based metrics for comparative analyses of urban dynamics that cannot generally be obtained from administrative definitions of urban extent. Mapping provides static snapshots of the urban mosaic while monitoring allows us to quantify the spatiotemporal dynamics. The free archive of imagery from the Landsat series of satellites allows mapping of urban extent in unprecedented detail and at a spatial scale sufficient to study the makeup of the built-up fabric and footprint (e.g. buildings, parking lots, roads).
The Global High Resolution Urban Data from Landsat data collection provides two examples of maps of urban extent across the globe derived from Landsat, and a third example of Landsat imagery for major cities of the world. The collection contains the following two companion data sets produced by NASA Goddard Space Flight Center and the Department of Geographical Sciences at the University of Maryland:
The third data set in this collection contains Landsat imagery for 77 major urban areas worldwide and the raw, underlying data for 28 of these areas: