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How to use USGS DLG vector data https://forum.transdem.de/viewtopic.php?f=6&t=27 |
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Author: | geophil [ 23 Jan 2011 19:26 ] |
Post subject: | How to use USGS DLG vector data |
DLG is a large scale US vector map, digitized from the USGS 1:24,000 topo map series. DLG stands for Digital Line Graph. One of its distribution formats is SDTS which TransDEM cannot read directly. However, after conversion to .dxf, the data can be used with TransDEM. The procedure is somewhat complex but should yield proper results, eventually. How to obtain the data
How to convert the data
How to process the data in TransDEM
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Author: | PDX-Mike [ 25 Apr 2011 09:16 ] |
Post subject: | Re: How to use USGS DLG vector data |
Apparently this data is no longer available in SDTS format (*.ddf file extension). The link in the original post is also dead (404 file not found). I did some hunting around and although I can find DLG large scale files, they are in a *.do file format?? |
Author: | geophil [ 25 Apr 2011 11:16 ] |
Post subject: | Re: How to use USGS DLG vector data |
Thanks for this information. I have done a bit of research myself now. It's not as bad as it seems, remedy is on its way: An alternative download address. (I will update the original tutorial later.) The new address is USGS Earth Explorer, as pointed to here: http://eros.usgs.gov/#/Find_Data/Produc ... lable/DLGs You need to register to be able to download. All in all it looks like a different user interface to the same data. |
Author: | PDX-Mike [ 26 Apr 2011 05:53 ] |
Post subject: | Re: How to use USGS DLG vector data |
Tried that site and registered. Downloaded a file for my local area to see what it was like. Unfortunately, as I mentioned above, the files they claim are in SDTS format are in native or optional format with only one file in the archive and it is a *.DO format. Appears to be text. Is this format something that TransDem can import? |
Author: | geophil [ 26 Apr 2011 08:35 ] |
Post subject: | Re: How to use USGS DLG vector data |
PDX-Mike wrote: Unfortunately, as I mentioned above, the files they claim are in SDTS format are in native or optional format with only one file in the archive and it is a *.DO format. Appears to be text. Here is what I did. Same example as in the first posting, for "Golden, CO".On the NewEarthExplorer site:
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Author: | PDX-Mike [ 27 Apr 2011 00:48 ] |
Post subject: | Re: How to use USGS DLG vector data |
I tried your example, and everything works fine. Apparently the problem is USGS only has limited SDTS formatted coverage. I found that it seems to be very hit and miss in my home state and in southern Washington state. There seems to be full coverage in native format, but not all areas have the SDTS format. I spot checked several places in Oregon and found that even following a rail line in the "earth explorer" window, I could find SDTS format only about half the time. The quick test is that if you only see 3 files pop up in the results, there is no SDTS format for that quad. I send USGS a message commenting on the lack of coverage and the fact that it is a bit of a pain to have to open the metadata to figure out what format the files are in. If you open the metadata, and look at the data format type if it is a 3 then it is SDTS, otherwise it is native. edit, just got a reply to my message, saying that someone will respond in a day... LOL we'll see. Also been playing around with one of the DLG files I did find, you might add to the tutorial that if the coordinates don't line up, you can close the route file, look at the metadata and see what was used, and set that in view/national coordinate system, then open the file again. In my case the DLG file I downloaded was UTM/NAD27. Even better might be to look at the metadata and jot down the coordinate system used while you're downloading the files... |
Author: | n2airb [ 08 Jul 2011 19:32 ] |
Post subject: | Re: How to use USGS DLG vector data |
Geophil, Hi my name is Shawn and I am new to Transdem on your " How to use USGS DLG vector data tutorial" you had a link for sdts2dxf any converters that work with windows 7 64 bit? your link will not work with win 7. 2nd question which site do you use for downloadable dems for Transdem? Have a good day Shawn. |
Author: | geophil [ 09 Jul 2011 14:00 ] |
Post subject: | Re: How to use USGS DLG vector data |
n2airb wrote: you had a link for sdts2dxf any converters that work with windows 7 64 bit? I haven't tested it on an x64 system it but to me sdts2dxf.exe appears to be an ordinary Win32 console application without any specific requirements.n2airb wrote: 2nd question which site do you use for downloadable dems for Transdem? For a US route I would recommend USGS NED DEMs, available on Seamless Server. You will find a short introduction in the TransDEM main manual. A much more detailed tutorial can be downloaded here in the forum.
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Author: | Redford1998 [ 19 Feb 2014 18:38 ] |
Post subject: | Re: How to use USGS DLG vector data |
Hello there, is there anyway I can use the data even though its an opt file? Is there any kind of free file converter I can use? |
Author: | geophil [ 25 Feb 2014 22:30 ] |
Post subject: | Re: How to use USGS DLG vector data |
I'm afraid, opt as a vector data format is unknown to me. I'm not sure (and my intenet connection is too limited at the moment to verify) but can't we obtain vector data in shape format via the National Map Viewer? |
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