Cleaning a .laz point cloud to obtain a DTM of only the ground
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Jorge Rodríguez
Mar 12, 2026, 5:02:25 PM (7 hours ago) Mar 12
to LAStools - efficient tools for LiDAR processing
Hey everyone, how are you?
Hey everyone, how are you?
Previously, I conducted a photogrammetric flight with a Phantom 4 Pro in a semi-desert area of San Luis Potosí, Mexico, where there are earthen embankments and shrubby vegetation. The tallest trees are mesquite trees, reaching 2 meters. I took 6 control points with GNSS antennas and from this, I obtained my orthomosaic, my DSM, and a DSM. The process is done in PIX4D Mapper. Now, reviewing the DEM, what I want to do is obtain a clean DTM, meaning one that doesn't include the embankments or the vegetation, only the ground height, to simulate a scenario without these features—that is, without vegetation and without those embankments (which are like plot dividers with a height of 90 cm). The DTM generated by PIX4D isn't entirely clean because it includes the embankments (obviously, since it's interpreted as a slope), but it also includes some vegetation heights. How can I clean the DSM to only show the ground heights and generate contour lines based solely on those? Heights without vegetation and edges. I tried to do it in Cloud Compare, but while it removes a lot of the vegetation, as I mentioned, it's mostly shrubby vegetation, much of it only 50 cm from the ground, and it doesn't remove it completely. I think that to remove those uneven areas (edges), I would have to do it manually. The problem is that I don't know how. I've read that LAStools can help in this process, but I'm relatively new to this powerful tool. I just installed it in QGIS and I'm learning how to use it. If you could guide me with a methodology to enhance this work, I would be very grateful.
Hey everyone, how are you?
Previously, I conducted a photogrammetric flight with a Phantom 4 Pro in a semi-desert area of San Luis Potosí, Mexico, where there are earthen embankments and shrubby vegetation. The tallest trees are mesquite trees, reaching 2 meters. I took 6 control points with GNSS antennas and from this, I obtained my orthomosaic, my DSM, and a DSM. The process is done in PIX4D Mapper. Now, reviewing the DEM, what I want to do is obtain a clean DTM, meaning one that doesn't include the embankments or the vegetation, only the ground height, to simulate a scenario without these features—that is, without vegetation and without those embankments (which are like plot dividers with a height of 90 cm). The DTM generated by PIX4D isn't entirely clean because it includes the embankments (obviously, since it's interpreted as a slope), but it also includes some vegetation heights. How can I clean the DSM to only show the ground heights and generate contour lines based solely on those? Heights without vegetation and edges. I tried to do it in Cloud Compare, but while it removes a lot of the vegetation, as I mentioned, it's mostly shrubby vegetation, much of it only 50 cm from the ground, and it doesn't remove it completely. I think that to remove those uneven areas (edges), I would have to do it manually. The problem is that I don't know how. I've read that LAStools can help in this process, but I'm relatively new to this powerful tool. I just installed it in QGIS and I'm learning how to use it. If you could guide me with a methodology to enhance this work, I would be very grateful.
Regards.
Jorge
Jorge Delgado García
Mar 12, 2026, 5:36:44 PM (7 hours ago) Mar 12
to last...@googlegroups.com
You can check ...
It is a excellent tutorial, but you need to take into account that you need a LAStools license in order to reach full potential of the software.
Jorge Delgado
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