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Author Topic: NAVD88 geoids from the website not correctly georeferenced  (Read 1232 times)

r.ravanelli@unibo.it

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NAVD88 geoids from the website not correctly georeferenced
« on: March 09, 2020, 09:34:48 PM »
All the geoids of the North American Vertical Datum 1988 available on the Agisoft Metashape website don't seem to be correctly georeferenced, how you can see from the attached figure.
All the geoids in the figure (EGM96, NAVD88-09, NAVD88-12b, CGG2013n83) have been download from the Agisoft Metashape website and opened in Qgis.
I've also did a test with GlobalMapper and with Google Earth Engine: the same problem occurs.
Can you please check if an error occurred when the heights of the NAVD88 geoids were computed or when the tiffs were uploaded on the website?
Thank you in advance!

r.ravanelli@unibo.it

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Re: NAVD88 geoids from the website not correctly georeferenced
« Reply #1 on: March 10, 2020, 05:11:08 PM »
All the NAVD geoids available on the Agisoft Metashape website are shifted of 360° in longitude.
The solution is to modify the geotransorm (for example with gdal) as follows:
gt_new = (gt[0]-360, gt[1], gt[2],gt[3],gt[4],gt[5])

Alexey Pasumansky

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Re: NAVD88 geoids from the website not correctly georeferenced
« Reply #2 on: March 10, 2020, 05:45:28 PM »
Hello r.ravanelli,

360 degree shift shouldn't affect the geoidal height interpretation in Metashape. However, if your observations are different, please let me know.
Best regards,
Alexey Pasumansky,
Agisoft LLC