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.
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, the Bureau of Land Management, and more. 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.
When logged onto a lab computer, navigate to afp://storageserver1.ads.carleton.edu/GISVOL/GIS/GISdata/USA or (M:\GIS\GISdata\USA).See the Carleton Spatial Analysis web site or contact Wei-Hsin Fu (x5733, firstname.lastname@example.org) for more information about data in this location.