Association of American Geographers |
Esri GIS Online This bibliography covers the literature of geographic information systems, science, and technology. It indexes journals, conference proceedings, books, and reports from the origins of GIS to the present. |
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Natural Earth |
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Science.gov A gateway to authoritative, selected science information provided by U.S Government agencies, including research and development results. |
Minnesota Maps Online |
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USGS Historical Topographic Map Explorer Uhe this tool to find historic topographic maps and overlay them on a modern map. Map download is available. |
U.S. Geologic Survey The USGS serves the Nation as an independent fact-finding agency that collects, monitors, analyzes, and provides scientific understanding about natural resource conditions, issues, and problems. |