How Do I Find GIS Data?

While this list is not exhaustive , its goal is to identify and provide access to as wide a variety of online GIS data and resources
as possible.

Framing Your Data Search

What geographic level are you trying to represent/analyze? What types of features do you need to represent?

For example,

Do you need to represent states, counties, cities (points or polygons), etc?
Do you need to see streets, water, elevation information?
Do you need parcel or ownership information?

Who would create this kind of data?

federal government (specific agency or branch?)
state government (specific branch or group?)
county government
city government
commercial entities
??????

Would this type of data be publicly available or restricted in some way?

Could the information be restricted to protect someone from harm?
Might the information be restricted because of privacy issues?
Other restrictions?

What data formats are you willing/able to work with?What kind of online tools might help you locate the data you need?

Data search tools.
Mapping tools that provide access to the data too.
Imagery search and or display tools.

GIS Data Web Sites

Web sites that consolidate many potential resources for locating GIS data at the world, national, state and local levels.
GIS Data
Selected web sites from the John R. Borchert Map Library.
Spatial Data at MIT
Browse the "on the web" links in the left hand navigation bar.
Websites for Digital GIS Data
Site from Stanford to help track down GIS data and imagery.

Specific GIS Search Tools

Federal Resources

Geospatial One StopYour one stop shop for locating federal and other level GIS data.
Advantages: Widely accepted as a central respository for federal data, some states include their data here too, some mapping capabilities to insure data is what you expect.

data.gov
New data site with a subset of federal data and geospatial data available.
Advantage: Can look easily for some specific formats including KML/KMZ and Shapefiles.

National Map Seamless Server
U.S. and international data.

USDA Geospatial Data Gateway
Click on Get Data.

EPA Enviromapper