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Author Topic: Tiled model higher than original elevation when using 5174  (Read 2383 times)

jackieryu

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Tiled model higher than original elevation when using 5174
« on: March 25, 2021, 01:22:49 PM »
Hello,

Using Metashape 1.6.5, we've processed a data set in EPSG:5174.

We exported the tiled model in Cesium tiles, but the resulting data is visualized higher than the original elevation of the DEM.

This happens only when using this coordinate reference system. We were wondering if this is a CRS specific issue. If so, are there any potential solutions?

Please find the attached screenshot to help with your understanding.

Thank you.

Alexey Pasumansky

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Re: Tiled model higher than original elevation when using 5174
« Reply #1 on: March 25, 2021, 08:40:19 PM »
Hello jackieryu,

Do you observe any altitude difference for the same XY point, when measuring coordinates in Metashape window over DEM in the Ortho view mode and over Tiled Model in the Model view mode?
Best regards,
Alexey Pasumansky,
Agisoft LLC

jackieryu

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Re: Tiled model higher than original elevation when using 5174
« Reply #2 on: March 26, 2021, 09:44:31 AM »
Thank you for the prompt response!

I've checked on the Metashape GUI, and it seems like the elevation profile are the same across the DEM, Point Cloud, and Tiled Model.

However, the problem seems to be present when I export the Tiled Models in Cesium 3D tiles.

Would it be possible to guide any way to solve this issue? Thank you.

Alexey Pasumansky

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Re: Tiled model higher than original elevation when using 5174
« Reply #3 on: March 28, 2021, 03:06:50 PM »
Hello jackieryu,

Cesium 3D tiles are exported in WGS84 coordinate system, do you use the same export option for the other products?

Bessel 1841 ellipsoid seems to be about 80 meters lower than WGS84.
Best regards,
Alexey Pasumansky,
Agisoft LLC

jackieryu

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Re: Tiled model higher than original elevation when using 5174
« Reply #4 on: March 29, 2021, 12:21:02 PM »
Hello,

Thank you for the insight! I think the Coordinate System could be the cause of the issue, as you kindly suggest.
However, when exporting the tiled model in Cesium format, I do not have the option to change the Coordinate System. Is there a solution to enable this option?

Thank you so much for the technical support!

Alexey Pasumansky

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Re: Tiled model higher than original elevation when using 5174
« Reply #5 on: March 29, 2021, 02:14:20 PM »
Hello jackieryu,

Tiled model in Cesium 3D tiles format can be only exported in WGS84 coordinate system.
Best regards,
Alexey Pasumansky,
Agisoft LLC