Bill Mixon said:
At least I figured out how to download an image of a topo map by
name from http://libremap.org/, something I never came anywhere
near figuring out at the official site http://seamless.usgs.gov/index.php.
In fact, those are seamless maps at that USGS site, without
the collar that has the legend and other useful information. And
yes, it has a terrible interface. After much searching around
various web sites, I finally found the main USGS topo map page at
<http://edc.usgs.gov/#/Find_Data/Products_and_Data_Available/DRGs>.
Topo maps are downloadable from the EarthExplorer page,
<http://edcsns17.cr.usgs.gov/EarthExplorer/>. Click on Digital Maps
at the left and then select DRG, which should appear in the Selected
Datasets box below. Then type in a place name in the search box and
then click on the search button to the right. An Area Selected box
will appear below the map. Then hit the search button at the bottom
of the page. Eventually you'll get to a place to download the map,
although it is certainly more cumbersome than a simple list of maps
if you already know the name of the one you want. You also have to
register (free) with the site in order to download. I like to
actually download topo maps rather than look at them online because
then I have them to refer to without having to go back and get them,
and I can manipulate them as I please.
The main USGS store web page
<http://store.usgs.gov/b2c_usgs/b2c/start/%28xcm=r3standardpitrex_prd%29/.do>
has a link to download topo maps free (on the right). That page has
a pretty good interface where you can enter the map name or a place
and find it on a map like in Google Maps or Map Quest and then
download the topo or other maps associated with it by following the
directions. These are GeoPDFs that are not as large as the regular
TIFF maps above, however, but they can be viewed with Acrobat Viewer
with appropriate plug-in. The large TIFF maps require a special
viewer like Global Mapper, the trial version of which you can use for
free, and which allows you to strip off the collars and seamlessly
display up to four topo maps at once. <http://www.globalmapper.com/>
The USGS store also has a caving poster under Education Products.
Mark Minton
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