This image showing Central Park in New York City contrasts the impervious surfaces in dark blue, surrounding the park, which in lighter blue. Screenshot from the Data Visualization and Access Tool, which was developed to use with the data sets Human Built-up and Settlement Extent (HBASE) and Global Man-made Impervious Surface (GMIS).
With more than half of the world’s population living in urban areas today, the mapping and monitoring of urbanization are critical to better understanding development patterns, and their potential impacts. Addressing this need are two new high resolution data sets released through the NASA Socioeconomic Data and Applications Center (SEDAC) operated by CIESIN that map global, man-made impervious surfaces and urban extents in unprecedented detail. The companion data sets, Human Built-up and Settlement Extent (HBASE) and Global Man-made Impervious Surface (GMIS), are among the first global, 30-meter spatial resolution data sets of their kind that are derived from the 2010 Global Land Survey (GLS) free Landsat archive. The data sets are expected to have a broad range of uses for those wishing to study the fine details of the urban fabric from local to global scales at full resolution, and those modeling climate and environmental impacts of man-made surfaces at continental to global scales. The production of HBASE and GMIS resulted from a collaboration between the NASA Goddard Space Flight Center and the Department of Geographical Sciences at the University of Maryland and was funded through the NASA Land Cover Land Use Change Program. The data sets are available for free download, with four representative maps illustrating the data layers.
Using the Data Visualization and Access Tool, users may view and download the GMIS and HBASE data sets by country, tile, shapefile, rectangle or polygon. Data are available at 30m, 250m, and 1km resolutions in either geographic or UTM projection. Users may also explore map layers from the GMIS and HBASE data sets, including the uncertainty layers, in a four-panel map view. Different map layers may be compared, or different areas of the same map layer. Features include the ability to zoom in to the native data resolution of 30-meter; to query pixel values; to display a layer full-screen; and more.