Image Gallery 8 - Using easily available data NHGIS has census data going back to 1790.

Making online maps using data sources like those provided by ArcGIS Online is relatively easy. Simply open a new map and add any of the thousands of readily available layers. However, incorporating historical data is not necessarily so simple. It often requires extensive research to find available data. Its accuracy, authenticity, and reliability needs to be examined. And, finally, data must be given appropriate geographic reference before a map can be made available to students in an easy-to-use form.

If you are lucky, the process may only require that you download shape and data files from a resource like NHGIS (National Historical Geographic Information System) and add them to your map. In the example here, census and agricultural census data were downloaded from the NHGIS for 1930, 1940, and 1950 and made part of a Dust Bowl map. Students can use the map to easily compare Great Plains demographic, economic, and agricultural data across two decades.