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Author Topic: Import German Geoid Model into Metashape  (Read 381 times)

Dieter

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Import German Geoid Model into Metashape
« on: September 13, 2021, 07:33:12 PM »
I have now tried to import a geoid for 3 hours. Every time I get the message "vertical date out of range" when I convert data into the new format. I have original data from the German institute BKG for
the quasigeoid in Germany.

There are several formats in the ascii, trimble topcon, leica etc.

Despite the exact instructions in the freshdesk "https://agisoft.freshdesk.com/support/solutions/articles/31000148332-how-to-use-height-above-geoid- for-the-coordinate-system "
And yes, I called Metashape as admin and my project is within the geoid boundaries.

I can't get it to work,


It's just frustrating! Who can help and has done something like this before?


thanks
Dieter

Paulo

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Re: Import German Geoid Model into Metashape
« Reply #1 on: September 14, 2021, 10:33:36 AM »
Hello Dieter,

i guess that the geoid file is private so sharing it would be a problem, no?

I would check the metadata of the Geoid Model you have created in Metashape geoids folder. As in following metadata extracted from Geobasis NRW undulationsmodell:

FILENAME=C:\Users\paul.pelletier\AppData\Local\Agisoft\Metashape Pro\geoids\Undulationsmodell_GeobasisNRW_v01.tif
DESCRIPTION=<Undulationsmodell_GeobasisNRW_v01.tif> VERT_DATUM["Geobasis NRW",2005]
...
PROJ_DESC=Geographic (Latitude/Longitude) / ETRS89 / arc degrees
PROJ_DATUM=ETRS89
PROJ_UNITS=arc degrees
EPSG_CODE=EPSG:4258
COVERED AREA=6491497 ha
LOAD TIME=40.13 s
GDAL_NO_DATA_VALUE=-3.40282e+38
NUM COLUMNS=13126
NUM ROWS=8186
NUM BANDS=1
PIXEL WIDTH=0.00028 arc degrees
PIXEL HEIGHT=0.00028 arc degrees
MIN ELEVATION=42.448 meters
MAX ELEVATION=48.483 meters
ELEVATION UNITS=meters
BIT DEPTH=32
SAMPLE TYPE=32-bit Floating Point
TIFF_DESC=VERT_DATUM["Geobasis NRW",2005]
GEOG_CITATION=ETRS89
PHOTOMETRIC=Greyscale (Min is Black)
BIT_DEPTH=32
SAMPLE_FORMAT=Floating Point
TILE_WIDTH=256
TILE_HEIGHT=256
COMPRESSION=LZW
PIXEL_SCALE=( 0.00028, 0.00028, 1 )
TIEPOINTS=( 0.00, 0.00, 0.00 ) --> ( 5.8312400024, 52.5709999995, 0.0000000000 )
MODEL_TYPE=Geographic lat-long system
RASTER_TYPE=Pixel is Area
VERT_DATUM=None Specified

to check that datum is ETRS89 and that all your project.s crs are referred to same datum. And description should be VERT_DATUM=["<Name of datum>",...
where <Name of datum> should be same as datum name you entered in Edit Vertical Coordinate System window during creation of your customized compound reference system....as in following

hope this makes some sense,
Best Regards,

Paul Pelletier

c-r-o-n-o-s

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Re: Import German Geoid Model into Metashape
« Reply #2 on: September 14, 2021, 10:47:09 AM »
Small side note...
Do not use the GeobasisV01.tif file. (from NRW)

According to my verification, this file was faulty. There is now a new and official one on the "Geobasis NRW" homepage.

@Dieter
Melde Dich per PM bei mir wenn es weiter nicht funktioniert.

Paulo

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Re: Import German Geoid Model into Metashape
« Reply #3 on: September 14, 2021, 12:26:49 PM »
Hello cronos,

I have not used the undalationsmodell NRW extensively, but I tested undulation values extracted from Undulationsmodell_GeobasisNRW_v01.tif  at 1 degree intervals with values obtained using interpolation utility offered by BKG http://gibs.bkg.bund.de/geoid/gscomp.php?p=g and they agree within 1 mm....
« Last Edit: September 14, 2021, 12:28:58 PM by Paulo »
Best Regards,

Paul Pelletier

Dieter

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Re: Import German Geoid Model into Metashape
« Reply #4 on: September 14, 2021, 04:14:01 PM »
Hello Paulo,

where or in which file can I find this metadata?

I only have one Tif file in the Geoid-Folder, and I'm surprised that it consists of a completely white area. The data basis is the sample data of the BKG from Lausitz / Germany.


Thanks
Dieter
« Last Edit: September 14, 2021, 04:17:54 PM by Dieter »

Dieter

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Re: Import German Geoid Model into Metashape
« Reply #5 on: September 14, 2021, 04:56:13 PM »
I have now loaded the NRW undulations model as a Tif, there is even a separate description for Metashape - what can I say, it doesn't work either.

As soon as I want to convert wgs84 into my new geoid model I get the error message "Error: Vertical datum out of range"

WGS84 coordinates are in NRW, i can't believe it.


Dieter

Paulo

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Re: Import German Geoid Model into Metashape
« Reply #6 on: September 15, 2021, 06:27:08 AM »
Dieter,

I have tested the GCG2016_NW geoid model placing 2 markers Point 1 and Point 2 with simulated OrthoHeight of 0 in ETRS89 / UTM zone 32N (zE-N) DHHN2016 height. Then I transformed to WGS84 without any problem. I also placed these 2 points in Metashape with CGCG_NW geoid model as layer and the extracted undulations correspond to value shown in Metashape....

So i do not know what is the problem on your side?
Best Regards,

Paul Pelletier

sfmdd

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Re: Import German Geoid Model into Metashape
« Reply #7 on: September 15, 2021, 08:23:15 AM »
Hello,

not a solution for your problem, but what i am doing is using the already integrated DHHN92 heights in metashape and set an offset when exporting the final products, which for my region is usually 2 cm.

I wasn't able to use the GCG2016 from saxony in metashape neither.

Greetings

c-r-o-n-o-s

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Re: Import German Geoid Model into Metashape
« Reply #8 on: September 15, 2021, 01:18:31 PM »
The data from this page definitely works.
(Germany/NRW free registration)
https://www.bezreg-koeln.nrw.de/brk_internet/geobasis/geodaetische_fachprogramme/transformation/echtzeit/index.html

Instructions on how to set it up should be included, or I can provide them.

You have to be careful with the non-TIF formats.
There was a bug before V 1.7 that the files were interpreted as mirror images.


Offsetting geoid heights does not work over a "long distance".
Depending on the length of the area, the deviation then goes into the cm range.
(I have an example where 4cm of undulations can be seen over a 1km length.)
« Last Edit: September 15, 2021, 01:26:32 PM by c-r-o-n-o-s »

Dieter

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Re: Import German Geoid Model into Metashape
« Reply #9 on: September 16, 2021, 09:11:17 AM »
Thank you for all your suggestions and tips, in the meantime I've got it running. I deleted the entire geoid folder again and tried it for a determined 20 times, after which it worked at some point. Whether it was because I was logged in as admin, because I tried it in an empty project or because I closed Metashape and opened it again afterwards - I don't know.

For our purposes as a surveying office in Germany, this is simply far too complicated. It would be a lot easier if I could define a separate geoid for each survey project with a separate undulation per project. Then I wouldn't need to buy the entire Germany Geoid, which costs 750 euros and I will never need it in my life.

Just to think about it.

Nevertheless, thanks again to everyone.

Dieter :)

c-r-o-n-o-s

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Re: Import German Geoid Model into Metashape
« Reply #10 on: September 16, 2021, 02:09:13 PM »
Quote
It would be a lot easier if I could define a separate geoid for each survey project with a separate undulation per project.

Of course it is possible...
(It says so on page 5 of my instructions).

Instead of "Add", enter "User-defined".
A fixed value can be entered there.

As already written, the lengths should not be too long.
(In NRW up to 4cm undulation change per 1km).

But then you can also stay in eleptoid heights and change the coordinates with a "Z-OFFSET" script.
(These scripts can be found at Agisoft).

https://github.com/agisoft-llc/metashape-scripts/blob/master/src/add_altitude_to_reference.py


Dieter

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Re: Import German Geoid Model into Metashape
« Reply #11 on: September 16, 2021, 03:18:15 PM »
The one with the user-defined height does not work, the message "the selected date is not available" appears

How do I get this to work?



Dieter

Dieter

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Re: Import German Geoid Model into Metashape
« Reply #12 on: September 18, 2021, 11:42:26 AM »
After hours of experimentation, I came across the solution.

Metashape only accepts one geoid per vertical coordinate system. If I select the German Main Elevation Network 2016 for Germany and then import the geoid from NRW, this geoid is always used, even if I import other geoid from Germany and name them differently. To use a different geoid (e.g. Rheinland Pfalz) I first have to completely delete the geoid from NRW. I didn't manage to run both geoids at the same time under different names. The same thing happens when I use a custom undulation, that doesn't work until I remove all the other geoids. I don't know if that's what the developers wanted, but for me it seems to be working for now.

Dieter