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Author Topic: Exported pointcloud appears as narrow line of points  (Read 2337 times)

wildtypitch

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Exported pointcloud appears as narrow line of points
« on: November 23, 2018, 08:16:00 PM »
I realise that this is because of the coordinate system as it only happens with georeferenced exports.
I believe I can apply shift to adjust the location so that it's within the bounds of the receiving applications limits, but how do I retain the correct geolocation information. Is this purely an issue with the CAD (revit) software I'm using?
Thanks

Alexey Pasumansky

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Re: Exported pointcloud appears as narrow line of points
« Reply #1 on: November 23, 2018, 08:57:10 PM »
Hello wildtypitch,

Such situation may happen if you are exporting the data in WGS84 (Lat/Long) system where X and Y units are in degrees and Z is in meters and the CAD application doesn't support such input and assumes that everything is in the same units.

If it is the case, then I can suggest to use some projected coordinate system on export or choose Local Coordinates option - it will keep the scale and orientation of the model, though the absolute coordinate information will be not accessible.
Best regards,
Alexey Pasumansky,
Agisoft LLC

wildtypitch

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Re: Exported pointcloud appears as narrow line of points
« Reply #2 on: November 26, 2018, 04:17:14 AM »
Thanks Alexey Yes that makes sense.
Local works. I'm trying to export as an EPSG:7405 Compound coordinate system (OSGB 1936 / British National Grid + ODN height)
And I get the dialogue error

"Selected vertical datum is unavailable. Please configure datum transformation"

Plain epsg27700 (without the vertical) translates fine. Wondering what I'm doing wrong? DO I need to put the EPSG:7405 prj file somewhere?

Thanks

Paulo

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Re: Exported pointcloud appears as narrow line of points
« Reply #3 on: November 26, 2018, 04:59:10 AM »
Hello wildtypitch,

in PS you can open the  reference settings window and configure your coordinate system by clicking the settings button next to Coordinate System drop down.. see attached screen capture...

in Datum Transformation Settings window, you should see an entry for geoid height (tif file giving difference between elipsoidal height and ortho height). If not present you can add it by using drop down menu....

Normally, you should have a tiff on your sytem defining ODN height or download it from geoids page http://www.agisoft.com/downloads/geoids/....

« Last Edit: November 26, 2018, 05:03:46 AM by Paulo »
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Paul Pelletier,
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Alexey Pasumansky

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Re: Exported pointcloud appears as narrow line of points
« Reply #4 on: November 26, 2018, 11:23:13 AM »
Hello wildtypitch,

Seems that in PhotoScan Pro 1.4.4 there's an issue that affects proper utilization of 7405 coordinate system, even with geoid model downloaded.

You can try to use Metashape Pro pre-release version (while we are preparing 1.4.5 update with bug-fixes):
- download OSGM15 geoid model (EPSG::5101) and put it to /geoids/ directory in Metashape Pro installation folder,
- run Metashape Pro and open your project,
- select EPSG::7405 for export.
Best regards,
Alexey Pasumansky,
Agisoft LLC