[Qgis-user] problème lors de l'export d'un nuage de points (LIDAR HD) en MNT

[Andrea Giudiceandrea]

Hi Pascal,
in my previous message I advised you to install QGIS LTR 3.40.7, not 
QGIS LTR 3.40.4.

Anyway, QGIS LTR 3.40.4 should also work (since the original error 
doesn't occur, according to the log), provided that your system has 
enough free resources to perform the task and that the algorithm's 
parameters value are correct.

It looks like this time the pdal_wrench application (which the 
processing algorithm relies on) crashed because you have set the 
FILTER_EXPRESSION parameter with an incorrect expression (previously you 
have set a different and correct expression, instead).

The expression "Classification = 2 OR 6" is incorrect.

An equivalent correct one is "Classification = 2 OR Classification = 6".

Moreover, are you sure your system has enough free RAM and storage space 
to process a copc file containing 32 millions points on a 1000m x 1000m 
area in order to create a 20'000px x 20'000px raster GeoTIFF (due to the 
fact that you have set RESOLUTION=0.05)?

Regards.

Andrea

Il 14/12/2025 15:21, Pascal WISSENBERG ha scritto:
> I installed version 3.40.4 ltr and when I use the same "export to 
> raster" algorithm, I get a new message:

> { 'FILTER_EXPRESSION' : 'Classification = 2 OR 6', 'FILTER_EXTENT' : 
> None, 'INPUT' : 'copc://E:/My Documents/QGIS/LIDAR 
> tiles/LHD_FXX_0801_6398_PTS_LAMB93_IGN69.copc.laz', 'ORIGIN_X' : None, 
> 'ORIGIN_Y' : None, 'OUTPUT' : 'E:/My Documents /QGIS/dalles 
> MNT/0801-6398k.tif', 'RESOLUTION': 0.05, 'TILE_SIZE': 1000 }

> The process stopped so unexpected