[GRASS-user] Re: Aster DEM

[Stefan Sylla]

Hi Javier,

EGM96 (I guess somethin' like 'Earth Geodetic Model') refers to the  
vertical datum. If
you only need relative height information (e.g. for watershed  
analysis), you do not need
information retrieved from the vertical datum. However, if you need  
absolute heights
(e.g. height above sea level), you should recalculate the height  
values (substract EGM96
offset from Aster DEM heights) according to the region of your DEM.

Hope that helps
Stefan

Quoting "Javier García [via OSGeo.org]"  
<ml-node+s1560n4650688h76 at n6.nabble.com>:

>
>
>
> Hi, I have a question that i hope you can help me.
> I want to use some aster Dem, but in specifications I read that   
> aster Dem is using EGM96
> geoid . Do I have to do something special to use those DEM's?
>
> The zone that I work is WGS84 147N.
>
> Thanks in advance for the answer.
>
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