Import of an georeferenced Point Cloud

[juliaa]

Hello dear FAQ team from CC,
I want to compare georeferenced point Clouds (about 15m x 15m) from PhotoScan and RealityCapture. So far I have used * .pts or * .xyz or * .txt for the import, but I get as an import result only a line with all my points. Which export file i have to use and what am I doing wrong?

Best regards
Juliaa

[daniel]

Maybe it's an an issue with the text file 'separator'? Have you tried changing it? (in the ASCII file import dialog).

Otherwise if you can share a sample file with me it may be easier to understand what's going wrong (cloudcompare [at] danielgm.net).

[daniel]

Oh, or do you mean that once loaded all the points seems to be aligned in 3D? In this case it's probably because the scale along one dimension (generally Z) is really different from the two other dimensions (X, Y). In this case, you need to rescale the corresponding dimension only (with 'Edit > Multiply/Scale' and only change one dimension so that the corresponding coordinate values have the same scale as the others).

[ffleury]

Hi! I'm having the same issue!

I import the georeferenced point cloud into CC and all my plot is aligned in on direction, as a big thin line! And that happens with other datasets to.

Any guess on how could I plot it right?


thanks in advance!

[daniel]

Oh, that's definitely because it's a geographic coordinate system. You have to load points in a 'projected' coordinate system (otherwise X and Y will be angular values, and Z in meters or equivalent...

[ffleury]

Bah, that really makes sense!

thanks for the fast reply.

[ffleury]

And what about when the opposite happens? I have a another dataset that has its XY coordinates beautifully displayed but it's totally flat.

474094.8 6669644 5.5
473916.7 6669934 8.7
474230.3 6669739 2.5
474534.6 6669252 1.4
474795.6 6669220 1.5
474396.2 6668776 1.5
474650.9 6668755 1.7
474905.4 6668704 1.6
474839.2 6668447 1.7
474509.7 6668355 1.5
474379.2 6668035 1.3
474638.7 6667929 2.3

that's an example of the xyz array in use.

[ffleury]

Anyone? =|

[daniel]

Here what's striking is the lack of digits (and therefore a probably low accuracy and resolution). If the coordinates are in meters, then the resolution is only 10 cm?! (at least accepting the Global Shift probably suggest by CC would make the cloud more 'balanced'). With such a poor resolution, you can try to activate the 'EDL' shader and increase the points display size to see some features better?)

[JoeKan]

By the looks of it, the program is not interpreting the space (_) as a separator. Replace the space (_) separator with a comma (,) in a text editor and try another import. I'm doing exactly that and the import works great.