Now that you’ve downloaded GeoPDF maps from USGS, let TerraGo help you do more with them!
TerraGo Toolbar is an extension for the Windows version of Adobe Reader. TerraGo Toolbar makes is easy to
 measure distances between objects, add your own comments to specific locations on the map, view the files in
conjunction with Google Maps or even integrate them with your GPS to track your position on the map.
And best of all - it’s free! Please also see the
TerraGo Toolbar training videos and the USGS US Topo GeoPDF Tutorial.