Using Python to send arguments to LAStools basics

Question

I'm currently trying to develop a LAStools specific routine, setting all the parameters for lasheight then using the output of that to run lasclassify. The closest thing I've found to being able to write this in Python is in Sending arguments to LAStools function from Python script not working

In the above post I'm a bit curious where the input and output .las files are. Also, not exactly sure how that Bat functionality is working. Does anyone have an example of a complete script they would be willing to post?

Here's what I have so far, I can't seem to get it to work though. I think it has something to do with the environments setting. I'm running the exact text from the bat file in the command line and it's working now that I updated the default PATH to where my LAStools bin folder is.

import os, random, sys, subprocess

input_path = "D:\Working_D\LAStools_scratch\input\\*.laz"
height_path = "D:\Working_D\LAStools_scratch\height"
arg_cores = "-cores 16"

directory = r'D:\Working_D\scripts\BatchFiles'
with open(os.path.join(directory, 'BatchTemp.bat'), 'w') as OPATH:
      OPATH.writelines(["lasheight ",
                        "-i {0} ".format('"' + input_path + '"'),
                        "{0} ".format(arg_cores),
                        "{0} ".format("-odir"),
                        "{0} ".format('"' + height_path + '"'),
                        "{0} ".format("-olaz"),
                        "\n "])

BatFile = 'D:\Working_D\scripts\BatchFiles\BatchTemp.bat'

proc=subprocess.Popen(BatFile,stdout=subprocess.PIPE,stderr=subprocess.PIPE,shell=True)
output,error=proc.communicate()

os.remove(BatFile)

print 'process complete.'

SOLVED: I was running this in IDLE and it would not work but running the Python script through the cmd window (e.g. D:\Working_D\scripts\lasheight_v2.py) and it worked!

Answer 1

Now that your question is open again I can provide some code. In your linked answer I wrote a batch file then called the batch file, that works, but to call directly from python:

lasheight     = r"c:\lastools\bin\lasheight.exe" # earlier in the script
for ThisXStep in XStep:
    for ThisYStep in YStep:
        # for each sub block identify the matching list
        InList = os.path.join(RasterTempDir,"LHInputList-{}-{}.txt".format(ThisXStep,ThisYStep))

        SInfo = os.stat(InList) # check the file size for the list. It is possible that some blocks are empty
        if SInfo.st_size > 0:
            print("Processing {}".format(InList))
            LASHeight = [lasheight,
                        '-replace_z',
                        '-drop_below',dropMin,
                        '-lof',InList,
                        '-drop_above',dropMax,
                        '-odir',ClampedFolder]            # the command I'm using for LASheight in a Popen list

            pcs =subprocess.Popen(LASHeight)              # start this process
            pcs.wait()                                    # and wait for it to finish

This is a part of a much bigger script; it contains just the information pertinent to your question. Previously in this script I wrote some text files (InList) which contain a list of the LAS files for a given block.