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Author Topic: custom vertical datum  (Read 991 times)

nik

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custom vertical datum
« on: January 25, 2022, 07:34:25 PM »
Dear all,

I am wondering how to define a polar stereographic crs based on EPSG::3413 but with a vertical datum referenced to mean sea surface within the python api. I have a global mean sea surface grid file in geotif format placed in metashapes geoids folder. I am also aware of running
Code: [Select]
crs.addGeoid() to put my tif file in metashapes registry. But how would I define this external vertical datum then? It should be something like EPSG::3413 + MeanSeaSurface.tif

Any help is appreciated, all the Best,

Nik       

Alexey Pasumansky

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Re: custom vertical datum
« Reply #1 on: January 25, 2022, 09:30:10 PM »
Hello Nik,

.addGeoid() function should be called to define the paths to all the geoid files that will be used in the project opened by the script. But it doesn't create the compound coordinate system definition automatically.

You need to create it manually (or via Coordinate System editor dialog from Metashape GUI) and use in your script by loading from PRJ file or by using its WKT definition as a text string.

Have you checked the related article already?
https://agisoft.freshdesk.com/support/solutions/articles/31000148332-how-to-use-height-above-geoid-for-the-coordinate-system
Does it help for your needs?
Best regards,
Alexey Pasumansky,
Agisoft LLC

nik

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Re: custom vertical datum
« Reply #2 on: January 29, 2022, 08:28:05 PM »
Dear Alexey,

thank you very much for your reply! The problem could be solved as explained. I was able to define the crs in the GUI, export it as *prj and import it in the python API.

Cheers,

Niklas