[GRASS-user] NASADEM: new global 1 arcsec DEM

[Markus Neteler]

Moin Robert,

On Fri, Jul 10, 2020 at 6:42 PM Robert Nuske <rsn.mailinglists at gmail.com> wrote:
>
> Moin Markus & Markus,
>
> did you use the NASADEM further than importing it in GRASS?

Well, I used it like a DEM..

> I need a DEM for Germany + 10km Buffer. So, I thought NASADEM would be a natural fit and am now trying to get a handle on this dataset.
>
> The import with r.in.nasadem in a WGS84 Location just worked.
> Thanks a lot metzm!
>
> The NASADEM documentation states, that the height of the merged DEM (NASADEM_HGT) is above EGM96 geoid and not WGS84 ellipsoid. I have no clue how to get from there to UTM32 with a height reference comman in Germany (DHHN92).
>
>
> Do you have any solutions or hints how to proceed?

According to the answer here
https://gis.stackexchange.com/questions/361240/are-wgs84-latlon-coordinates-and-egm96-latlon-coordinates-the-same-and-differenc

the math would be a r.mapcalc formula.

Time ago I played with
https://grasswiki.osgeo.org/wiki/Global_datasets#EGM2008_Geoid_Data_.28Earth_Gravitational_Model.29

The EGM96 data appear to be here as interpolated grid:
https://earth-info.nga.mil/GandG/update/index.php?action=home

Please let us know how it goes.

Best,
markusN