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<div class="moz-cite-prefix">On 12/2/13 9:51 AM, Ian Dees wrote:<br>
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cite="mid:CAG91b3R1tzZ0U9Gpg_59cbdRDhjMmffTtyeWSGv1APZQMhUELA@mail.gmail.com"
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<div dir="ltr">The "USGS Scanned Topos" layer is a cached layer
based on the three layers here:
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<div><a moz-do-not-send="true"
href="http://raster.nationalmap.gov/ArcGIS/rest/services/DRG/TNM_Digital_Raster_Graphics/MapServer">http://raster.nationalmap.gov/ArcGIS/rest/services/DRG/TNM_Digital_Raster_Graphics/MapServer</a><br>
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<div>I don't see a good way to check metadata for the scanned
quads. There's information about the "Large Scale Imagery"
layer, but not the scanned topos.</div>
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it'd be good to try to figure a way out to do that, although<br>
i realize it may not be feasible. the problem is that when<br>
you're looking at a quad and you don't know the age of<br>
the data, it's hard to assess it's value vs other data you may<br>
have in front of you.<br>
<br>
i currently have the 2003 GPS traces the ATC supplies for the<br>
Appalachian Trail north of Salisbury, CT which differ from<br>
what the USGS quad layer shows. it is almost certainly the case<br>
that the USGS quad is out of date by decades and the ATC data<br>
represents the current trail routing, but i'd love to eliminate<br>
that 1% of doubt.<br>
<br>
i guess what it comes down to is that the USGS quads are good<br>
for topo data but otherwise they're basically historic documents.<br>
<br>
richard<br>
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