Using @earth_relief_01s without filling missing data

Q&A
1

I’m working on a GMT script that will enable GMTSAR to directly get an SRTMGL1 arcsec elevation dataset for a specific area using @earth_relief_01s, but we’d rather it did not fill in ocean / missing areas with the global @earth_relief_15s. I’d rather it just provides zero or NaN for those areas; possibly it should just give an error if the whole region is outside the SRTM tiles. Is it possible in GMT to prevent the masking/filling step when requesting this remote dataset?

2

Hi Eric.

I am also working on a similar script. Try @srtm_relief_01s.

3

Aha, yes that is perfect, thanks! @Esteban82 if you pull the latest GMTSAR version on github, there is already a new script there called ‘make_dem.csh’ that will do this process; currently it uses @earth_relief_01s but we’ll probably update to this one to be more consistent. Users will still be on their own outside +/-60 deg. latitude.

4

This script, right?

Where I can get the geoid_egm96_icgem.grd ? Do you donwload a grid from the ICGEM? With what resolution?

5

The geoid grid has been added to the GMTSAR distribution - https://github.com/gmtsar/gmtsar/blob/master/gmtsar/geoid_egm96_icgem.grd. If you update to the latest version it will be placed in the folder pointed to by ‘gmtsar_sharedir.csh’.

6

Ok, Many thanks,

BTW, I think you will find the script usefull (https://github.com/gmtsar/gmtsar/issues/389).

7

Very nice, thanks!