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GeoCommunity - DEM FAQ
- Where can I find a digital file of the USGS quad grids?
- Question: The DEMs I need to seem to available here, what should I do?
Answer: You can search for DEMs using Earth Explorer(EE) at
http://earthexplorer.usgs.gov
Although EE only searches on native format DEMs, GeoCommunity should have
the most recent SDTS DEMs on their web site. For example, if EE shows that
a native format DEM is available in 10 meter, then GeoCommunity should have
the 10 meter SDTS file available.
-
I need help deciphering the USGS DRG naming conventions... do you have a resource for me?
- Question: I can't convert the updated DEM data using the SDTS2DEM translator (Sol Katz utility) and I've never had problems before?
Answer: Gregg Townsend, Staff Scientist at The University of Arizona has an updated version available at http://www.cs.arizona.edu/topovista/sdts2dem.html
- Question: I downloaded some DEMs from the GISDataDepot and they appear to be corrupt, what should I do?
Answer: If you believe there may be a problem with an individual data set or if you
need additional information about SDTS, please access the SDTS web site at
http://mcmcweb.er.usgs.gov/sdts/ or send email to sdts@usgs.gov.
- Question: Is there a dedicated SDTS mailing list or similar resource?
Answer: You bet!. Details on this can be found at http://www.gisdatadepot.com/dem/sdtslist.html
- Question:
I recently downloaded (from the geocomm site) a couple of
SDTS DEM tiles that seem to have invalid elevations. (Using
DLG Viewer v3.7, for example, reports the elevations as
"Invalid height"
Answer:
It appears that you have downloaded 10 Meter SDTS DEMs where the units are
decimeter. Unfortunately, dlgv32 does not view the decimeter DEMs
correctly. More information about the changes to the SDTS DEMs can be
found at: http://mcmcweb.er.usgs.gov/sdts/
- Question:
What software do I need to work with SDTS format DEMs?
Answer:
There are a number of commercial programs as well as freeware translators that you can use. One of the most popular translators (SDTS2DEM) has recently been updated. See also: http://software.geocomm.com/translators/ and http://software.geocomm.com/viewers/raster/
Other Programs:
- ArcInfo 8, ArcView 8 via ArcToolbox.
- ArcView3.2 (requires editing of xxxxIDEN.DDF)
- ERDAS Imagine 8.4 (requires editing of xxxxIDEN.DDF )
- GRASS 5
- FME
- 3DEM
- MicroDEM
- WCS v5
- IDRISI
- MapInfo 6.5 (Universal Translator from SAFE)
- Question:How can I get DEM data into AutoCAD in either DWG or DXF format?
Answer:SDTS DEM's can be converted to ASCII XYZ files using the MICRODEM software
package. This software is available for download at
http://www.usna.edu/Users/oceano/pguth/website/microdem.htm
Please keep in mind that the data served up and distributed by the GeoCommunity/GISDataDepot is public domain data that has been developed by public agencies. These are not commercial data products. The GeoCommunity is not responsible for errors or positional innacuracies that may be discovered in the data.
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