ign-pdal-tools

Python utilities for working with LiDAR point clouds and LAS/LAZ files with PDAL. The tools were developed for the LidarHD project at IGN. The library is maintained to meet the team's needs and may change over time.

What it does

Imagery

• color.py adds RGB, infrared, or vegetation-index values to a point cloud using imagery from Geoplateforme or a local raster.
• download_image.py downloads georeferenced GeoTIFF imagery from Geoplateforme and combines tiled requests for large extents.

Point-cloud editing

• add_points_in_pointcloud.py adds vector points or samples along vector lines to a LAS/LAZ file. It supports an altitude attribute for 2D input and configurable classification and spacing.
• las_clip.py crops a LAS/LAZ file to a 2D bounding box.
• replace_area_in_pointcloud.py replaces points within areas defined by a vector file with points from another cloud.
• las_add_extra_dims_from_las.py copies missing or selected dimensions from a donor file by matching points. It also supports processing matching filenames in two directories.
• las_remove_dimensions.py removes dimensions, and las_rename_dimension.py renames them.
• replace_attribute_in_las.py maps values in a LAS/LAZ attribute using a JSON correspondence map.

LAS/LAZ information and quality checks

• las_info.py reads metadata, bounds, tile origins, and EPSG information.
• pcd_info.py provides tile-origin utilities for point-cloud coordinate bounds.
• check_las.py checks whether PDAL can read a file, with an optional retry and a decorator for validating generated files.
• las_comparison.py compares selected or all dimensions in two files, with optional numeric tolerances.
• count_occurences counts attribute values across LAS/LAZ files. Use count_occurences_for_attribute.py to create JSON counts and merge_occurences_counts.py to combine results.
• estimate_and_compare_trajectory.py estimates a sensor trajectory from multiple returns and can compare it with a reference trajectory.

Format and pipeline utilities

• standardize_format.py rewrites a LAS/LAZ file in the library's standard format.
• run_pdal_pipeline.py runs a PDAL pipeline provided as JSON against an input file and writes the output file.
• unlock_file.py works around malformed TerraSolid LAS 1.4 files with point formats 6-10 that lack the global-encoding WKT flag.
• create_random_laz.py generates synthetic LAZ files with configurable point format, CRS, classifications, and extra dimensions for testing.

Neighboring tiles

• las_merge.py merges a tile with its neighboring tiles.
• las_add_buffer.py adds points from neighboring tiles along a tile's border.
• Both tools use filenames to determine tile extents and locate neighbors. The expected pattern is {prefix1}_{prefix2}_{xcoord}_{ycoord}_{postfix}, for example Semis_2021_0770_6278_LA93_IGN69.laz. By default, coordinates are in kilometers and tiles are 1 km by 1 km.

Python examples

Read LAS metadata:

from pdaltools import las_info

metadata = las_info.las_info_metadata("input.laz")

Infer a tile origin from point-cloud bounds:

from pdaltools import las_info, pcd_info

metadata = las_info.las_info_metadata("input.laz")
bounds = las_info.get_bounds_from_header_info(metadata)
origin_x, origin_y = pcd_info.infer_tile_origin(*bounds, tile_width=1000)

Install and use

Install from PyPI:

pip install ign-pdal-tools

For development, make install creates or updates the pdaltools mamba environment from environment.yml.

To build and run the tools in Docker, see Dockerfile and the Makefile targets below.

Development

• Create or update the environment: make install
• Run the standard test suite: make testing (excludes tests marked geopf)
• Run all tests, including geopf tests: make testing_full
• Install pre-commit hooks: make install-precommit
• Record changes in CHANGELOG.md and update the version in pdaltools/_version.py when appropriate.

Build and package commands are defined in the Makefile:

• make build builds the Python package.
• make deploy uploads the built package to PyPI.
• make docker-build builds the Docker image.
• make docker-test runs the tests in Docker.
• make docker-build-custom-pdal builds an image with the custom PDAL version configured in the Makefile.