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Author Topic: Downloading NED in GeoTiff format  (Read 1883 times)

93ToyTruck

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Downloading NED in GeoTiff format
« on: September 11, 2015, 08:50:33 PM »
I can no longer download GeoTiff NED data using the "National Map Seamless Server"(links from the California.xls file):
http://www.gpsfiledepot.com/tutorials/100k-quad-lists-and-dem-links-for-each-state/

I've been trying randomly over the last several weeks. It always says that there are 2 or more requests ahead of me and times out before finishing. I have a feeling that the service has been shut down and no longer available. Does anybody have any insight?

I need the GeoTiffs for Dem2Topo. Is the only option to convert ArcGrid to GeoTiff? Are there any other ways to get the GeoTiff data? I downloaded some ArcGrid files from the National Viewer and the files cover 1/4 of the area. I really prefer the larger files.

Thanks


maps4gps

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Re: Downloading NED in GeoTiff format
« Reply #1 on: September 11, 2015, 11:38:21 PM »
USGS Seamless Server - 'It always says that there are 2 or more requests ahead of me and times out before finishing.'   -  That is a surprising message as USGS discontinued that method of obtaining their date 2 or 3 years ago.   Data is now obtained through the National Map interface; originally prestaged 1x1 degree files could be obtained via selecting larger areas in the map view, however, it seams recently this has been restricted to selecting one 1x1 degree area at a time.  There may be other methods; however, for me obtaining the most recent data from USGS has become too needlessly time consuming.

93ToyTruck

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Re: Downloading NED in GeoTiff format
« Reply #2 on: September 12, 2015, 05:26:14 PM »
The link that they email is a static link to an FTP server. You can browse the directory and get what you want if you remove the zip file name. It's a lot easier than going through the map viewer UI.

I used the Seamless Server within the last year. The larger files are a lot easier to work with. I should have downloaded more when I had the chance.

93ToyTruck

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Re: Downloading NED in GeoTiff format
« Reply #3 on: September 15, 2015, 08:50:03 AM »
More info...
The datasets in the National Viewer are 1x1 degree so they're twice the size as the files from the Seamless Server. When I performed a search, I selected a 1x1 degree index but the results display files for adjacent areas so it looks like multiple files are needed for the selected area.

The data from the seamless server had small gaps between the files. The data from the National Viewer slightly exceeds the bounds so you end up with overlap unless you trim before merging.

I sent an email to the USGS about the seamless server and they responded with this URL: http://www.mrlc.gov/viewerjs/
Data \ Download Tool provides the same functionality as the old Seamless Server.

The links in the state spreadsheets will work if you change the URL from extract.cr.usgs.gov to landfire.cr.usgs.gov.

 

anything