This guide provides a comprehensive list of online sources of geospatial data. Many of the sources on this list are websites of government agencies or organizations that provide open access to the vector and raster geospatial data that they have collecte
While some datasets are relatively easy to find because there is a clear provider of the desired information (e.g. the U.S. Census Bureau for detailed U.S. demographic information or the City of Austin for city zoning data) other datasets can be much harder to locate and may require extensive use of online search engines to find. The most difficult situations are those in which you are not sure if the data exists at all online and must weigh pros and cons of continuing to search and potentially finding the desired data versus spending more time searching for data that does not in fact exist and still not finding anything useful. When using search engines like Google, Bing, or Duck Duck Go it is important to choose the terms in your search query carefully as even a small change in your phrasing can yield dramatically different search results. For instance, if looking for geospatial data that you can use to a make a map of all state funded universities in the United States queries like "university data", "united states university map data", "u.s. university geospatial information" might not produce the results you are looking for. While these searches might give you links to sites that have interesting information about university enrollments, graduation statistics, or financial data they are unlikely to link you to data that you can bring directly into GIS software to design your map. Searches that include terms like "GIS", "shapefile", or "geodatabase" are much more likely to yield results that link you to useful geospatial datasets. When searching for data online it is also useful to try a data focused search engine like those listed below as they will provide specialized functionality that can help you restrict results by important dataset characteristics.