[GRASS-user] NASA to release no cost 30m DEMs with world-wide coverage on 29 June

[Michael Barton]

I've tended to consider SRTM to have a slightly better vertical  
accuracy and ASTER DEM to have a better horizontal resolution. There  
are other differences too. ASTER DEMs are created using stereoscopic  
imagery (forward and backward band 3 near IR) and SRTM is radar. So  
ASTER DEMs are affected by clouds and by surface vegetation, and  
pretty much stop at the coast.

Michael
____________________
C. Michael Barton, Professor of Anthropology
Director of Graduate Studies, School of Human Evolution & Social Change
Director, Center for Social Dynamics & Complexity
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: <www.public.asu.edu/~cmbarton>




On Jun 26, 2009, at 12:48 AM, Micha Silver wrote:

> Thanks, Michael. That's great news.
> What do you make of the 20 m./30 m. vertical/horizontal accuracy  
> statement?
> Isn't SRTM supposed to be around 15 m. vertical and <10 m. horizontal
> (even tho' it's 90 m. resolution)?
>
> Regards,
> Micha
>
> Michael Barton wrote:
>> See the following announcement. NASA (USA) will release high
>> resolution DEM's of the globe, produced from the Terra ASTER
>> satellite, at no charge. You can check out the web announcement at
>> <https://lpdaac.usgs.gov/lpdaac/about/news_archive/monday_june_22_20092 
>> >.
>> As a Terra ASTER user, I'