Dems finding

Lalla · April 25, 2011, 03:50:07 AM

Where I can find dem that not are of Usa but of other world places, as Europe, Asia, and so on?

Oshyan · April 25, 2011, 04:06:34 AM

http://earthexplorer.usgs.gov

- Oshyan

Lalla · April 25, 2011, 05:50:53 AM

Thanks a lot.

Happy Easter.

Lalla · April 25, 2011, 01:17:28 PM

I've difficult on what data sets download.
Can you help me?

Thanks.

Oshyan · April 25, 2011, 07:11:14 PM

SRTM is probably best. Try following Ryan Archer's DEM tutorial and adapt the steps for use on the Earth Explorer site (it's similar to the Seamless site he uses): http://www.archer-designs.com/tutorials/terragen2/usgs-data-terragen-2/

- Oshyan

Lalla · April 26, 2011, 04:27:39 AM

Earth explorer seems a pay to download site...

RArcher · April 26, 2011, 10:43:20 AM

It depends on what type of data you are trying to download. The EarthExplorer website brings in many sources of data both free and for pay. The steps to use the site are as follows:

1. Select your search criteria.
2. Select the data sets of interest (For DEM information look under the "Digital Elevation" heading. Likely there will only be SRTM data available.
3. Download whatever results are given.

Lalla · April 26, 2011, 01:22:09 PM

I've tried to download some data for test.
It seems has some troubles.

This is a terrain test that I made:

Uploaded with ImageShack.us

I don't know what're those spikes that are'nt on real place.

Tangled-Universe · April 26, 2011, 02:25:36 PM

I think these are holes in the dataset and there's little you can do about it I'm afraid.
It's possible the same area is available without holes in the dataset but perhaps not for free.
That sometimes happens, that you need to pay for something

RArcher · April 26, 2011, 02:36:06 PM

Martin is correct. Whatever version of the data you downloaded has portions missing. You can try the following site: http://srtm.csi.cgiar.org/

The version 4 of the SRTM data should have the missing parts resampled with other sources to eliminate most problem areas.

Roberts · April 27, 2011, 04:32:23 PM

Hi!
You can also try Jonathan de Ferrantis site: http://www.viewfinderpanoramas.org/
He has done some incredible work enhancing Nasa's srtm dems. He has filled some of the voids and spikes of the original data. He has also produced dems for areas which are not covered by srtm at all, concentrating on the mountainous regions in the world. Since your image shows a mountain landscape, maybe you can find a good dem there?

Here is the coverage for 3 arcsecond srtms:
http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org3.htm

And 1 second srtm:
http://www.viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org1.htm

Good luck!

Regards

Robert

pw_evc · April 27, 2011, 10:15:01 PM

Its feels inappropriate to plug the company I work for, but for high-res DEMs from all over the world, try East View Cartographic (www.cartographic.com). Beware, our site, for the most part is not very good. We are in the midst of an overhaul. We do SRTM (90m res) void fill as well as create 30m res DEMs from topographic maps. We can also create high-res DEMs (2-3m) from satellite/aerial imagery as well as radar and LiDAR derived DEMs too. Its a shot in the dark that we'll have one already made for the exact AOI someone is looking for, but if the exact location doesn't matter, then the cost won't be nearly as much.

FYI - I've recently become a licensed T2 user. I'm not just on here to plug my company. I'm actually in the process at this moment of trying to use T2 to create a virtual fly-thru of a valley in NW Argentina using a 2m DEM derived from 50cm GeoEye-1 imagery.

Okay, back to trying to figure out T2. Actually, if anyone has any pointers on the steps, and missteps, on loading real terrain data andn imagery into T2, please let me know.

Thanks,
Peter