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Author Topic: Add Greek Grid Geoid  (Read 3246 times)

dstefanakis

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Add Greek Grid Geoid
« on: December 30, 2019, 11:02:34 AM »
Dear Agisoft,

Kindly add the following geoid for Greek datum transformations, all available files are [url]here[http://users.ntua.gr/chiossif/pitsis/geoid/geoid.html/url],
I've tried to insert it by myself, even tried to modify the file encoding to match the ones from downolad section with no results.  I always get the Cant load geoid meassage at startup console.

Best regards and happy new year to everybody!!
Dimitris

JMR

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Re: Add Greek Grid Geoid
« Reply #1 on: January 11, 2020, 04:10:10 PM »
You can add this geoid and build by yourself a variation of epsg 2100
I've just done and it worked well with the geotif in the link you posted
Regards
GEOBIT

dstefanakis

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Re: Add Greek Grid Geoid
« Reply #2 on: January 11, 2020, 07:53:56 PM »
Dear Geobid,
Thanks for the kind reply.
Ive tried that already and iam must be doing something wrong... A tutorial would be helpful, or if it is not to much to ask, can you share the produced geoid so i could add it?

Best,
Dimitris

Alexey Pasumansky

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Re: Add Greek Grid Geoid
« Reply #3 on: January 12, 2020, 05:27:32 PM »
Hello Dimitris,

Please check the following tutorial which describes the way of converting the undulation grid information from external format to Metashape-accepted GeoTIFF:
https://agisoft.freshdesk.com/support/solutions/articles/31000148332-how-to-use-height-above-geoid-for-the-coordinate-system
Best regards,
Alexey Pasumansky,
Agisoft LLC

dstefanakis

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Re: Add Greek Grid Geoid
« Reply #4 on: January 12, 2020, 09:49:19 PM »
Thanks Alexey!!

I ll try again tomorrow and will report back.

dstefanakis

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Re: Add Greek Grid Geoid
« Reply #5 on: January 13, 2020, 12:56:58 PM »
Nada....

Although i followed the tutorial several times and i am supposed to be a GIS expert, agisoft doesnt seem to like the 32b float tiff file... even i f manage to load the file at the custom vertical datum, the popup message inform me for " Vertical datum out of range"....

I googled the forum for similar problems, restarted metashape, runned it as admin, but still the same! Also console at startup informs me that " cant load geoid"

Alexey plz give it a try

My goal is to directly transform the WGS84 coordinates of my cameras, given the fact i have an RTK l1 l2 capable UAS, to GREEK GRID, with accurate Z transformations.

Best regards,
Dimitrios

ps. i will keep to torturing my self and if i make it i will report back

dstefanakis

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Re: Add Greek Grid Geoid
« Reply #6 on: February 24, 2020, 06:14:14 PM »
Hello Dimitris,

Please check the following tutorial which describes the way of converting the undulation grid information from external format to Metashape-accepted GeoTIFF:
https://agisoft.freshdesk.com/support/solutions/articles/31000148332-how-to-use-height-above-geoid-for-the-coordinate-system

After all this time, ive made hundreds of tryouts following the tutorial.
The closest ive managed was using the carlson file (*.gsf) containing the Greek grid Geoid from my RTK controller and added as per instructions. That was the only file that actually was accepted and loaded. But still, most of the times i either get a msg that vertical datum is not supported or simply my z transformations are way of.

The file i used and worked is here https://filebin.net/uequng6jwz3v42fy

Any ideas? A readymeady file from an expert maybe?

Best regards,
Dimitris