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Free, downloadable USGS topo maps in geoPDF format

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Thanks to a post by member honeybee77 in the National Map Corps forum, I just learned about the topo quadrangle (and other) maps available from USGS in the geoPDF format.


The format, used as an free extension added to your PDF viewer (apparently only Adobe Reader and Acrobat are supported) adds certain map-friendly functions. TerraGo Technologies, which developed the add-on, describes it this way:

The free GeoPDF Toolbar turns Adobe Reader into a powerful geospatial application that gives users the ability to view, manipulate and update mapping data while leveraging Adobe collaboration capabilities to share information with others in the field and at home base.


Perhaps the most compelling feature of the GeoPDF Toolbar is its ease of use. Most everyone is comfortable with the way a PDF file works, so most people can begin using the GeoPDF Toolbar with little or no training.

Much of the added functionality will be similar to users of Doug Cox's fine USAPhotoMaps program, though there are differences.


You can download the geoPDF-formatted topo maps from the USGS store (if that very long link doesn't work, try http://tinyurl.com/2u7klu, or navigate from the USGS store home page: click on "Map Locater and Downloader," which is currently a prominent link in the News category.


The USGS geoPDF files are very high resolution scans, and the geoPDF toolbar gives you the ability to check distances and compute areas. (The extension also supports layers for additional information, but the scanned topo maps don't include this data.) The files are very large, ~10 MB/quad, and apparently have to be downloaded one at a time, at least through the public web interface. (There's probably some FTP backdoor.)


The interface is interesting, as it uses Google Maps, on which it overlays USGS quad names and boundaries. In addition to the usual 'map,' 'satellite' and 'hybrid' views, it also offers a 'topo' view, which is seamlessly tiled much the way USAPhotoMaps is. Those interested in Google Maps mashups may find this particularly interesting.


Both USAPhotoMaps and the geoPDF topo maps offer multi-segment measuring, the former program allows the user to go from quad to quad as it if were all one sheet and allows import and display of benchmark locations or other data via .loc, .gpx files. The USGS geoPDF maps are page oriented so if you want to move to the next quad you have to download and view it separately, but it gives you much better zooming possibilities than I have discovered in USAPhotoMaps. I don't see any obvious way to import and display data either.



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