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by handystack
3896 days ago
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I have mixed feelings about USGS topo maps these days. On the positive side, they are producing revisions much more frequently than in the past and they have made available high quality digital images of these maps for free. The availability of high resolution image files is really nice if you have a big screen and a powerful computer handy, but not so nice if you are scouting for berries on logging roads in a pickup and need something that you can stuff in your pocket. The USGS stopped doing big lithographic print runs of their maps, and the new inkjet prints are garbage in comparison. Whenever I find a lithographic print of a quadrangle I am interested in, I buy two or three because I know I may not be able to find them in the future. Also, the newer revisions (the ones including satellite images) seem like they get much less individual attention from the cartographers. Labels and symbols are less intuitively laid out. The difference between the new and old map styles is similar to the difference between musical scores generated by a computer and lightly edited by a copyist, and scores created by a master plate engraver. I vastly prefer the maps from the 80's and early 90's. |
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The old topo maps were compiled, drawn, and edited by hand, from primary sources. Look at an old topo and notice the different symbols for barns and houses, outline vs filled squares. They were able to mark those because a usgs employee went out in the field and checked each building. The result of this process were extremely accurate and detailed maps but it was very expensive. It took hundreds of person-hours for each map.
The new topos are produced from remote sensing data, mainly imagery and lidar, and are highly automated. They are worse in most ways(but quickly improving!) than the old maps but take much, much less person time, less than 10 minutes per map. This time is mostly spent verifying/cleaning the source data.