further functions of las2dem
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Basti
Jan 4, 2022, 3:01:47 AM1/4/22
to LAStools - efficient tools for LiDAR processing
Hey all,
"-step", "0.001", "-force_precision", "-attribute", "6", \
"-false", "-set_min_max", "-auto", \
"-odir", output_path_tiff, \
"-o", save_tiff_falsecolor])"
Many thanks and best regards!
with great pleasure I use the tool las2dem for student activities and investigations to rasterize results from point cloud comparisons and have them output to me as TIFF. The whole thing is done within an automated process with Python.
I would like to ask if there is an overview of all possible functions of las2dem via the command line. Since some things in the GUI can not be selected manually, what I have however already seen in some YouTube tutorials.
In my example, I would like to rasterize mainly after the deformations in the millimetre range. The histogram of the generated tiff should adjust and stretch automatically (without fixed limits) to the existing minimum and maximum values. However, my attempt so far did not work flawlessly, among other things because the attribute order of the read-in las-file strangely swaps every now and then...
Apropos - the generated TIFF of the actual values cannot be viewed in a standard viewer, because it is only white (I did not succeed in stretching the histogram manually via the usual Python libraries, probably because of the decimal values) - however, the display works without problems via QGIS. The simple Code is:
I would like to ask if there is an overview of all possible functions of las2dem via the command line. Since some things in the GUI can not be selected manually, what I have however already seen in some YouTube tutorials.
In my example, I would like to rasterize mainly after the deformations in the millimetre range. The histogram of the generated tiff should adjust and stretch automatically (without fixed limits) to the existing minimum and maximum values. However, my attempt so far did not work flawlessly, among other things because the attribute order of the read-in las-file strangely swaps every now and then...
Apropos - the generated TIFF of the actual values cannot be viewed in a standard viewer, because it is only white (I did not succeed in stretching the histogram manually via the usual Python libraries, probably because of the decimal values) - however, the display works without problems via QGIS. The simple Code is:
"subprocess.Popen([las2dem, \
"-i", input_M3C2, \"-step", "0.001", "-force_precision", "-attribute", "6", \
"-false", "-set_min_max", "-auto", \
"-odir", output_path_tiff, \
"-o", save_tiff_falsecolor])"
Do you possibly have some tips for me on this?
Many thanks and best regards!
Basti
Support at rapidlasso
Jan 4, 2022, 3:17:13 AM1/4/22
to LAStools - efficient tools for LiDAR processing
Hi Basti,
happy new year (@all readers!) and thanks for using LAStools.
About your main question:
*Documentation of the parameters*
You have 2 sources:
- See the [toolname]_README.txt file. You will find this in the .\bin directory near the exe of the tool. This is the reference documentation.
- See the [toolname].exe -h output. In your case: Run las2dem -h
About your other questions or may issues: If you want me to have a close look at this: Please describe it more precise. Give some sample of your output. Describe what you got as result and what you expect. Give some sample data so I can reproduce the whole thing. If you do so I am quite optimistic that we can help you.
Jochen @rapidlasso
Basti
Jan 5, 2022, 5:18:56 AM1/5/22
to LAStools - efficient tools for LiDAR processing
Hi Jochen,
Happy New Year to you too, and thank you for the answer.
Specifically, I would like to derive one or more TIFFs from a transformed point cloud consisting of the differences. The attribute to be rasterized is attribute no. 6.
Case 1: The TIFF is to contain the real values so that, based on these in a later display, further code takes over the colouring of the TIFF by a colour scheme defined with changeable values. However, the output can only be displayed well with QGIS to date.
Case 2: For a quick internal check whether the measurement has worked without looking at an extremely large amount of data in the point cloud or visualizing Case 1 in an elaborate way, a false colour image of the situation is to be displayed, stretching the existing histogram or their values (-0.14xx - 0.00xx m) to the colour scale. So in principle -set_min_max function, but other values can always come out here and exactly this should therefore automatically determine and use minimum and maximum values of the image (attribute 6). So to speak, a "determine_min_max" function, which I am looking for.
Attached I have loaded some files into the cloud, I hope this will make things clearer:
Happy New Year to you too, and thank you for the answer.
Specifically, I would like to derive one or more TIFFs from a transformed point cloud consisting of the differences. The attribute to be rasterized is attribute no. 6.
Case 1: The TIFF is to contain the real values so that, based on these in a later display, further code takes over the colouring of the TIFF by a colour scheme defined with changeable values. However, the output can only be displayed well with QGIS to date.
Case 2: For a quick internal check whether the measurement has worked without looking at an extremely large amount of data in the point cloud or visualizing Case 1 in an elaborate way, a false colour image of the situation is to be displayed, stretching the existing histogram or their values (-0.14xx - 0.00xx m) to the colour scale. So in principle -set_min_max function, but other values can always come out here and exactly this should therefore automatically determine and use minimum and maximum values of the image (attribute 6). So to speak, a "determine_min_max" function, which I am looking for.
Attached I have loaded some files into the cloud, I hope this will make things clearer:
Many thanks and best regards!
Basti
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