These shapefiles are derived from U.S. Government sources. Included with each shapefile
is a .met file. This is the metadata file that will give you detailed information about 
the sources of the data and what it contains.

If you are new to GIS you can learn more and download a free GIS program to use with
these shapefiles.  Go to:

  http://www.mapcruzin.com/free-learn-to-map-gis-tutorial-and-shapefile-atlas.htm
  
for more information.

For other free GIS programs and resources check:

  http://www.mapcruzin.com/free-gis-software-tools.htm
  
For more free GIS shapefiles check:

  http://www.mapcruzin.com/download-free-arcgis-shapefiles.htm
  
For interactive maps and data about nuclear power plants around the world check:

  http://www.mapcruzin.com/low-level-radiation/
  
And, if you haven't already done so, go here:

  http://feedburner.google.com/fb/a/mailverify?uri=blogspot/mapcruzin&loc=en_US
  
to signup for updates.

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