Subject Research Guides
GIS and GeoSpatial Data
Where to Start
Finding the right data for your GIS can be challenging. Before you start your search, be sure you can articulate what kind of data you need. Selecting the right data in the beginning will save time in the end.
Bringing together maps and data from twenty federal agencies, the National Atlas makes it possible to view, query, print, and download geospatial data for the entire United States. This source is best used for finding and viewing small-scale geospatial data.
National Map Viewer
Use the National Map to view selected data layers from the U.S. Geological Survey, U.S. Forest Service, U.S. Fish and Wildlife Service, and the Bureau of Land Management. The National Map is a collaborative project to provide current data and maps to the public. Data and maps can be viewed with merely a web browser, printed, or downloaded for use with GIS software. This is a great source for topographic maps (or data layers) and Digital Orthophoto Quadrangles.
Part of the Geospatial One-Stop E-Gov initiative, this web site allows one to search or browse data categories of geospatial information. The GeoData Map Viewer allows you to view multiple Internet map services (like the National Map) using just your browser. Map servers viewable include the USGS, FEMA Hazard Maps, NASA Globe program, NOAA, and the BLM. State and regional servers are being added, including the Minnesota Metro GIS Data Finder.
EROS Data Center
Browse by type of data to find aerial and satellite imagery, elevation data, land cover, digital line graphs (DLG) and digital raster graphics (DRG). This site only provides links for downloads and does not allow for previewing the data.
General Digital Data Information
This page provides links to data provided by the USGS including digital elevation models (DEM), digital line graphs (DLG), digital orthophoto quadrangles (DOQ), the National Hydrography dataset (NHD), the National Elevation dataset (NED), and other thematic digital data.
This page provides links and information for acquiring topographic maps, digital raster graphics (DRG), thematic maps, and planetary maps and images
Bureau of the Census - Geography
The U. S. Census is a major source of data used for mapping with GIS. The page linked here gives an overview of the resources provided by the census, along with links, such as TIGER, LandView, Census Tract Resources, and reference resources.
Geography Network Explorer(ESRI)
The Geography Network Explorer is a service provided by ESRI. Use it to find data, maps, and GIS content from agencies and commercial data providers. It is also possible to publish data to the Geography Network. The web site's accompanying documentation is very helpful, making this an especially good place for those new to GIS to begin their search.
GIS Data Depot
This site offers an intuitive interface that makes it easy to browse quickly to data available from different sources in varied formats. Not all data from this site is free, so be pay close attention to notices about cost. The smaller the geographic coverage, the more likely it will be that data will be available for free download (e.g. county data is more likely to be free than state data).
GIS at NITLE
The link above leads to a page with about 25 web sites that offer GIS data and resources provided from the National Institute for Technology and Liberal Education. Use the links on the left side of that page to find more sources for GIS.
This free service is probably the fastest way to get topographic maps and aerial photos and orthophotos. Newer versions may be found from the agencies that actually produce them.
Often it is the case that national data does not provide geospatial data in units small enough for a local study. Often the information needed is collected instead by state, regional, or county agencies. Contact one of the librarians below or come to the reference desk for help identifying potential sources of information to answer your research question.
Minnesota Data Deli
The first stop for Minnesota data is the Minnesota Data Deli.
Minnesota Geographic Data Clearinghouse
This site offers many ways to access data, including the Minnesota GeoGateway, which simultaneously searches across agencies that distribute digital geographic data. Particularly helpful is a set of links to data organized by data theme (e.g. where to go for aerial photography or for soil data).
This online GIS application allows you to make maps online with layers from many different agencies. Data is available for download as well. This is a great example of how communities can use GIS.
Starting the Hunt: Guide to Mostly On-Line and Mostly Free U.S. Geospatial and Attribute Data
This guide from the University of Arkansas Libraries includes extensive links to sources of information organized by state. This is a great place to begin looking for data in other states. It includes links to national data and attribute sources as well.
Tutorials and introductions to GIS can be found on the web. GIS.com (another site from ESRI) offers a very nice introduction, including explanations of GIS, geographical and cartographical concepts, and links to live data, data for download, and more information.
Also, try a general web search for gis tutorials and limit to educational instututions. For example, in Google, type:
"gis tutorial" site:.edu
The GIS community is an active one and there are many listservs and blogs to which you can subscribe, for example, Free GIS Data & Imagery GeoBlog.