Now that we covered where to find free GIS software in the last edition of the Free For All, it is time to discuss places to find the fuel that stokes your GIS fire. Free and open data has become relatively commonplace, which makes for an easier job when searching for geospatial data. Whether it is at the local, county, state or federal level, GIS datasets are available in all shapes and sizes. When looking for specific small-scale data, one can usually navigate to their area of interest, Boulder, Colorado, for example, and find a free data portal. There are several sources for large-scale datasets, such as demographic information, which can be found on the US Census Bureau website or websites such as Data.gov.
Finding local data over the United States or Canada is usually quite easy as most large cities (and many counties) have their own free data portals, for example, the city of Vancouver’s open data portal, or Summit County Colorado’s open data portal. Your data needs can also be theme-based rather than location based, if that is the case, you will find free options too! For example, if it is satellite imagery, there are a few sources for free, high-quality mapping data. My first and top recommendation is the USGS Earth Explorer. With the Earth Explorer, you have access to LANDSAT, MODIS, NAIP and a wide variety of other satellite and aerial imagery datasets. Users can register for free, giving them more access than guests. Other sources of free imagery include LandViewer, NASA Earthdata search and NASA EarthObserver, which allow you to either download images of a region of interest or download napping datasets such as active fires.
If you are looking for climate data, the USGS and NOAA have a plethora of datasets, as does the UNEP (United Nations Environmental Programme) Environmental Data Explorer. For a theme-based list of datasets Robin Wilson’s list of free GIS data sources is a great resource. Other useful websites include OpenStreetMap Data Extracts (geofabric downloads), which contains pre-processed and formatted datasets that are easy to use; as well as DIVA-GIS Data, which is a free GIS that also has its own website with loads of worldwide layers, global climate data, DEMs and more.
This list of free GIS data sources is by no means comprehensive as there are a plethora of free portals, often in local languages. I encourage you to search with specific keywords that include terms like GIS or shapefiles, as there is a high chance the data you need has already been collected and uploaded to the internet.
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