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Author Topic: WGS84 to EPSG31700 transform fails with 2.12m towards west on Metashape V1.5.2  (Read 1650 times)

dramida

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I noticed a more than 2 m shift on X in my final EPSG31700 (Stereografic 1970) after converting measured control points with Metashape V1.5.2 build 7838.
I also noticed 20 cm on Z difference.
I checked with a GNSS who offers the results in Stereo70 and i got about 2.11 m offset between it and Agisoft transform of WGS84 to Stereo70/EPSG31700.
I double checked with online app who transform WGS Lat& Long to Stereo, link below, and i got exactly 2.12 m shift on West
http://www.geo-spatial.org/transdatonline/
You may use the app called TransDatRO to check the transform.
Note than ETRS89 and WGS84 have the same Lat, Long and height for Romania.
Picture below shows the difference between measurements of the same points with different GNSS, straight in Stereo70 and transformed through Agisoftt Metashape.

ps. i own a student licence of Metashape Agisoft.


Alexey Pasumansky

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Hello dramida,

Which datum transformation parameters you are using in Metashape to define TOWGS84 parameters for EPSG::31700 system?

Can you provide coordinates in WGS84 and measured in EPSG::31700 for a few points from your project, so that we could try to preform the conversion and see the difference on our side?
Best regards,
Alexey Pasumansky,
Agisoft LLC

dramida

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Hello, i did two tests:

1- i compared two GNSS, one native in EPSG31700 and the other GNSS in EPSG4326 then transformed in EPSG31700 using Agisoft. The results are shown in table above. 2.11 m to east agisoft transform.

2- I took the same EPSG4326 measurements from EMLID  GNSS receiver and transformed it using an online tool to convert to EPSG31700. The results are the same, 2,12 m offset against Agisoft transform on X and 39 cm on Z. Y is the same in Agisoft and TransLT.

See files attached.