Import DEM's?

Started by astronut80920, August 10, 2017, 03:34:41 pm

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astronut80920

I have been attempting to import DEMS into TG for a while with poor results.  I am using TG free edition.  what I end up seeing on my view is what looks like a possible terrain, small, with a large block of black with spikes coming out of the top and interspersed with white pixels.  I tried changing position with no luck.  This happens to any DEM I import.  Anyone know what is happening and how do I import DEM's correctly?

Thanks for any help,

Jim Lawrence

DannyG

Quote from: astronut80920 on August 10, 2017, 03:34:41 pm
I have been attempting to import DEMS into TG for a while with poor results.  I am using TG free edition.  what I end up seeing on my view is what looks like a possible terrain, small, with a large block of black with spikes coming out of the top and interspersed with white pixels.  I tried changing position with no luck.  This happens to any DEM I import.  Anyone know what is happening and how do I import DEM's correctly?

Thanks for any help,

Jim Lawrence


What format are you loading? From the sounds of it you have a poor resolution DEM
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astronut80920

that's what I'm doing.  I found out that that probably won't work and I need to use GEOTiff files that are supposed to be available on the government USCS sites which brings up another problem.  When I attempt to download from these sites, all I see is a blank page or I can't find GEOTiff's on those sites.  What I need to do is find sources for these files.

Jim L

DannyG

Quote from: astronut80920 on August 11, 2017, 12:41:05 pm
  What I need to do is find sources for these files.



Scroll down to Real World Data. There are a bunch of links, some you need to create a profile but they are worth it.
http://www.nwdastore.com/links/
New World Digital Art
www.NwdaGroup.com
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Oshyan

It sounds like you are probably getting DEM data that has either 1: "nodata" zones that show up as big spikes, or 2: other garbage/bad/out of range data.

You can try to fix problem #1 by setting nodata zones to 0 using the option in the heightfield loader. If that doesn't address it, then finding other DEM data may be better. I find the data from the USGS through the National Map Viewer and Earth Explorer to both be good, and GeoTIFF is usually an option:
https://viewer.nationalmap.gov/launch/
https://earthexplorer.usgs.gov/

- Oshyan