Writing LAZ file using laspy

Question

I am new for handling lidar data. Actually I am using laspy for read and write laz file. I am using following syntax for writing LAZ file. It is created LAZ file on specified folder path but it took more size comparing with the input LAZ (Ex: input laz 50 mb , Output LAZ 450 mb ).

How do I resolve this?

        output_File="c:\test.LAZ"
        out_file = laspy.file.File(output_File, mode = "w", header=in_file.header)
        out_file.points = point_records
        out_file.close()

Answer 1

https://github.com/grantbrown/laspy says

Laspy is a pythonic library for reading, modifying and writing LAS files. Support for LAZ is limited to reading LAS version 1.0-1.3 files.

laspy does not have support for writing files in the LAZ format.

Answer 2

I strongly recommend PDAL for such DTM file handling and processing. I am not sure laspy directly supports compressed LIDAR format or requires extra plugin, but with PDAL you can convert between many formats, apply filters like minimum/maximum elevation, reproject etc.

Below is a small example.

import pdal
import json
pdal_pipeline = {
        "pipeline": [   
            *las_files,
            {
                "type":"filters.merge",
                "tag":"merged",              
                
            },
            {
                "type":"filters.reprojection",
                "in_srs":"EPSG:4326",
                "out_srs":"EPSG:32635"
            },
            {           
              "type":"writers.las",                     
              "filename": "merged_reprojected.laz"
            }
        ]
    }
pipeline = pdal.Pipeline(json.dumps(pdal_pipeline))
pipeline.execute()