Hi Javier,
<br/><br/>EGM96 (I guess somethin' like 'Earth Geodetic Model') refers to the &nbsp;
<br/>vertical datum. If you only need relative height information (e.g. for &nbsp;
<br/>watershed analysis), you do not need information retrieved from the &nbsp;
<br/>vertical datum. However, if you need absolute heights (e.g. height &nbsp;
<br/>above sea level), you should recalculate the height values (substract &nbsp;
<br/>EGM96 offset from Aster DEM heights) according to the region of your &nbsp;
<br/>DEM.
<br/><br/>Hope that helps
<br/>Stefan
<br/><br/>Quoting &quot;Javier GarcĂ­a [via OSGeo.org]&quot; &nbsp;
<br/>&lt;<a href="/user/SendEmail.jtp?type=node&node=4650802&i=0" target="_top" rel="nofollow" link="external">[hidden email]</a>&gt;:
<br/><div class='shrinkable-quote'><br/>&gt;
<br/>&gt;
<br/>&gt;
<br/>&gt; Hi, I have a question that i hope you can help me.
<br/>&gt; I want to use some aster Dem, but in specifications I read that &nbsp; 
<br/>&gt; aster Dem is using EGM96
<br/>&gt; geoid . Do I have to do something special to use those DEM's?
<br/>&gt;
<br/>&gt; The zone that I work is WGS84 147N.
<br/>&gt;
<br/>&gt; Thanks in advance for the answer.
<br/>&gt;
<br/>&gt; _______________________________________________
<br/>&gt; grass-user mailing list
<br/>&gt; <a href="/user/SendEmail.jtp?type=node&node=4650802&i=1" target="_top" rel="nofollow" link="external">[hidden email]</a>
<br/>&gt; <a href="http://lists.osgeo.org/mailman/listinfo/grass-user" target="_top" rel="nofollow" link="external">http://lists.osgeo.org/mailman/listinfo/grass-user</a><br/>&gt;
<br/>&gt;
<br/>&gt; _______________________________________________
<br/>&gt; If you reply to this email, your message will be added to the &nbsp; 
<br/>&gt; discussion below:
<br/>&gt; <a href="http://osgeo-org.1560.n6.nabble.com/Aster-DEM-tp4650688p4650688.html" target="_top" rel="nofollow" link="external">http://osgeo-org.1560.n6.nabble.com/Aster-DEM-tp4650688p4650688.html</a><br/>&gt; To start a new topic under Grass - Users, email &nbsp; 
<br/>&gt; <a href="/user/SendEmail.jtp?type=node&node=4650802&i=2" target="_top" rel="nofollow" link="external">[hidden email]</a>
<br/>&gt; To unsubscribe from Grass - Users, visit &nbsp; 
<br/>&gt; <a href="" target="_top" rel="nofollow" link="external">
        
<br/><hr align="left" width="300" />
View this message in context: <a href="http://osgeo-org.1560.n6.nabble.com/Aster-DEM-tp4650688p4650802.html">Re: Aster DEM</a><br/>
Sent from the <a href="http://osgeo-org.1560.n6.nabble.com/Grass-Users-f3884509.html">Grass - Users mailing list archive</a> at Nabble.com.<br/>