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#1 2020-06-08 04:45:26

Buster452
Member
From: Arizona
Registered: 2020-04-14
Posts: 34

USGS Topo Map Scans have things erased from them...

I have access to some older USGS maps and I'm seeing cases where some points of interest are partially removed from the USGS Topo Maps we have access to.   Usually there is still a symbol left on the scans we have access to (like a dot usually), but the name of the point has been removed.

Anyone else notice this?  Feels like they're erasing places from maps to hide them from others finding them.

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#2 2020-06-08 05:20:27

Carnildo
Member
Registered: 2017-10-18
Posts: 5

Re: USGS Topo Map Scans have things erased from them...

Do you have an example?  There are a number of cases near me where a placename has disappeared from the map, but every time I've looked into it, it's because the place has also disappeared (typically, these are farming communities that were abandoned during the Great Depression).

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#3 2020-06-19 18:05:18

Buster452
Member
From: Arizona
Registered: 2020-04-14
Posts: 34

Re: USGS Topo Map Scans have things erased from them...

Take a look at 33.5855496, -111.3780561

That's Skull Cave..

https://ngmdb.usgs.gov/topoview/viewer/ … /-111.3816

The Mormon Flat Dam 1/24000 topo from 1964 shows it.

Then look at the Topo's included with JOSM.  There's a little marker on the map that looks like a tipped over "Y" but the place name is gone.


There is a cave there.


I've also run into Ruins that have been removed from newer topos that are still on the ground, but not listed on newer topos.

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#4 2020-06-20 05:42:56

Carnildo
Member
Registered: 2017-10-18
Posts: 5

Re: USGS Topo Map Scans have things erased from them...

In the specific case of Skull Cave, the name only appears in the 1964 series of 1:24000 maps, not the 2004 series or the US Topo maps.  I'd guess that when they re-surveyed the area for the 2004 series, they found that the name was no longer in use -- it's no longer "Skull Cave", but just an unnamed cave.

There are two sets of USGS topographic maps out there.  There are the "classic" maps, produced prior to 2008, and the "US Topo" maps, produced since June of 2009.  The older maps are based on extensive fieldwork, while the newer maps are based on combining various geospatial datasets, and are generally very low-quality.

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