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Drone survey: import your pointcloud with correct georeference


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When you import a point cloud as is - without centering it on the internal origin as to keep it in its geolocation, you will get a point cloud that is visually corrupted, as in, it will have ugly lines... and the x,y coordinates say 0 while you can see in the rulers that is not the case...

Some time ago I reported this as a bug. I think it still is, as this should work properly so not to loose the correct georeferencing and have a nice workable point cloud.

pointcloudcorruptScreenshot2024-04-17at15_40_55.png.06da95f85886a348c56126ef3d8cc5b2.png

 

The solution I found for this now is

1. import the geotiff generated by the drone (using the settings of the geotiff - units and EPSG)

then

2. adjust the internal and user origin so they coincide with the midpoint of the geotiff 

and finally

3. import the point cloud ticking the box 'Center Import on Internal Origin'

 

So - you need to export a geotiff and a point cloud from your drone to be able to use the pointcloud in GIS

 

RESULT of 1-2-3

Screenshot2024-04-17at15_43_26.png.ae7def2717e8501e98aa2afed78171d3.png

Edited by Carol Reznor
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8 minutes ago, Carol Reznor said:

When you import a point cloud as is - without centering it on the internal origin as to keep it in its geolocation, you will get a point cloud that is visually corrupted, as in, it will have ugly lines... 

Some time ago I reported this as a bug.

 

This is a massive pain. I submitted a bug about it as well. VB-202892. It's crazy that you have to jump through these kinds of hoops in order to import a point cloud into a georeferenced file.

 

13 minutes ago, Carol Reznor said:

The solution I found for this now is

1. import the geotiff generated by the drone (using the settings of the geotiff - units and EPSG)

then

2. adjust the internal and user origin so they coincide with the midpoint of the geotiff 

and finally

3. import the point cloud ticking the box 'Center Import on Internal Origin'

 

Is Step 4 to Set User Origin to match the Georeferencing coordinate system?

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3 minutes ago, Tom W. said:

Is Step 4 to Set User Origin to match the Georeferencing coordinate system?

@Tom W.

 

That is a good practice I find and my personal preference to indeed set it (the user origin) back to match the CRS - especially if you export to DWG because otherwise the DWG will read what the rulers say and import incorrectly ( check the box export dwg with georeferencing puts a Geographic marker in the file in autocad) ... BUT for architects... if you want to export to IFC you shouldn't as IFC only works with 1 origin, so in that case they (internal and user origin) should stay in one place.

 

hoop hoop hoop 🙂

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  • 1 month later...

So... in a following project... this seems to not work as the orthophoto and the pointcloud are NOT exactly the same. They cover a different area so the midpoint of both objects is not the same... 
Back to square one... no good way to georeference a pointcloud. 

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