The more complicated stuff

Using laspy’s public api from laspy.file.File and laspy.header.HeaderManager objects will get you a long way, but sometimes it’s neccesary to dig a little deeper. For example, if you would like to build a 1.1 version file from a 1.2 version file, there is no automatic function to do this for you. Life becomes easier when we dig into some of laspy’s internal functionality:

from laspy import file as File
from laspy import header
import copy

# Open an input file in read mode.
inFile = File.File("./laspytest/data/simple.las",mode= "r")

# Call copy on the HeaderManager object to get a more portable Header instance.
# This means we don't  have to modify the header on the read mode inFile.
new_header = copy.copy(inFile.header)
# Update the fields we want to change, the header format and data_format_id
new_header.format = 1.1
new_header.pt_dat_format_id = 0

# Now we can create a new output file with our modified header.
# Note that we need to give the file the VLRs manually, because the low level
# header doesn't know about them, while the header manager does.
outFile = File.File("./laspytest/data/output.las",
                    mode= "w",
                    vlrs = inFile.header.vlrs,
                    header = new_header)

# Iterate over all of the available point format specifications, attepmt to
# copy them to the new file. If we fail, print a message.

# Take note of the get_dimension and set_dimension functions. These are
# useful for automating dimension oriented tasks, because they just require
# the spec name to do the lookup.

for spec in inFile.reader.point_format:
    print("Copying dimension: " + spec.name)
    in_spec = inFile.reader.get_dimension(spec.name)
    try:
        outFile.writer.set_dimension(spec.name, in_spec)
    except(util.LaspyException):
        print("Couldn't set dimension: " + spec.name +
                " with file format " + str(outFile.header.version) +
                ", and point_format " + str(outFile.header.data_format_id))

# Close the file

outFile.close()