[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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