LASR Python Bindings

Python bindings for the LASR (pronounced "laser") library - a high-performance LiDAR point cloud processing library.

Overview

The LASR Python bindings provide a clean, Pythonic interface to the powerful LASR C++ library for processing large-scale LiDAR point clouds. The API closely mirrors the R API, ensuring consistency across language bindings.

Features

• High Performance: Direct bindings to optimized C++ code
• Complete API Coverage: All LASR stages and operations available
• Pythonic Interface: Natural Python syntax with operator overloading
• Pipeline Processing: Chain operations for efficient processing
• Multi-threading Support: Leverage multiple cores for processing
• Memory Efficient: Minimal memory overhead through C++ backend
• Rich Results: Access detailed stage outputs and processing statistics
• Structured Error Handling: Comprehensive error information and debugging
• Flexible Input Paths: Pass a directory/catalog or an iterable of path-like objects; only .las/.laz files are used

Installation

Prerequisites

• Python 3.9+
• pybind11
• C++17 compatible compiler
• GDAL (>= 2.2.3)
• GEOS (>= 3.4.0)
• PROJ (>= 4.9.3)

Build from Source

cd python
pip install -e .

or using setuptools directly:

cd python
python setup.py build_ext --inplace

Quick Start

import pylasr

# Create a simple processing pipeline
pipeline = (pylasr.info() + 
           pylasr.classify_with_sor(k=10) + 
           pylasr.delete_points(["Classification == 18"]) +
           pylasr.write_las("cleaned.las"))

# Set processing options
pipeline.set_concurrent_points_strategy(4)
pipeline.set_progress(True)

# Execute pipeline (returns rich results)
files = ["input.las", "input2.las"]
result = pipeline.execute(files)

API Structure

Core Classes

Pipeline

Container for multiple stages with execution management.

# Create empty pipeline
pipeline = pylasr.Pipeline()

# Add stages
pipeline += pylasr.info()
pipeline += pylasr.classify_with_sor()

# Set processing strategy
pipeline.set_concurrent_files_strategy(2)

# Execute pipeline  
result = pipeline.execute(["file1.las", "file2.las"])

Processing Strategies

LASR supports different parallelization strategies:

# Sequential processing
pipeline.set_sequential_strategy()

# Concurrent points (single file, multiple cores)
pipeline.set_concurrent_points_strategy(ncores=4)

# Concurrent files (multiple files, single core each)
pipeline.set_concurrent_files_strategy(ncores=2)

# Nested strategy (multiple files, multiple cores each)
pipeline.set_nested_strategy(ncores1=2, ncores2=4)

Available Stages

Input/Reading

• reader() - Basic point cloud reader
• reader_coverage() - Read points from coverage area
• reader_circles() - Read points within circular areas
• reader_rectangles() - Read points within rectangular areas

Classification & Filtering

• classify_with_sor() - Statistical Outlier Removal classification
• classify_with_ivf() - Isolated Voxel Filter classification
• classify_with_csf() - Cloth Simulation Filter (ground classification)
• delete_points() - Remove points by filter criteria
• delete_noise() - Remove noise points (convenience function)
• delete_ground() - Remove ground points (convenience function)
• filter_with_grid() - Grid-based point filtering

Point Operations & Attributes

• edit_attribute() - Modify point attribute values
• add_extrabytes() - Add custom attributes to points
• add_rgb() - Add RGB color information
• remove_attribute() - Remove attributes from points
• sort_points() - Sort points spatially for better performance
• transform_with() - Transform points using raster operations

Sampling & Decimation

• sampling_voxel() - Voxel-based point sampling
• sampling_pixel() - Pixel-based point sampling
• sampling_poisson() - Poisson disk sampling for uniform distribution

Rasterization & Gridding

• rasterize() - Convert points to raster grids (DTM, DSM, CHM, etc.)
• rasterize_triangulation() - Rasterize triangulated surfaces
• focal() - Apply focal operations on rasters
• pit_fill() - Fill pits in canopy height models

Geometric Analysis & Features

• geometry_features() - Compute geometric features (eigenvalues, etc.)
• local_maximum() - Find local maxima in point clouds
• local_maximum_raster() - Find local maxima in rasters (tree detection)
• triangulate() - Delaunay triangulation of points
• hulls() - Compute convex hulls

Segmentation & Tree Detection

• region_growing() - Region growing segmentation for tree detection

Data Loading & Transformation

• load_raster() - Load external raster data
• load_matrix() - Load transformation matrices

I/O Operations

• write_las() - Write LAS/LAZ files
• write_copc() - Write Cloud Optimized Point Cloud files
• write_pcd() - Write Point Cloud Data files
• write_vpc() - Write Virtual Point Cloud catalogs
• write_lax() - Write spatial index files

Coordinate Systems

• set_crs() - Set coordinate reference system

Information & Analysis

• info() - Get point cloud information and statistics
• summarise() - Generate summary statistics

Utility & Development

• callback() - Custom callback functions for advanced processing
• nothing() - No-operation stage for debugging
• stop_if_outside() - Stop processing if outside bounds
• stop_if_chunk_id_below() - Conditional processing based on chunk ID

Comparison with R API

The Python API closely mirrors the R API structure:

R	Python
exec(pipeline, on = files)	pipeline.execute(files)
pipeline + stage	pipeline + stage
with = list(ncores = 4)	pipeline.set_concurrent_points_strategy(4)
filter = "Z > 10"	filter = ["Z > 10"]

Contributing

See the main LASR repository for contribution guidelines.

License

GPL-3 - see LICENSE file for details.

Links

• Main LASR Repository
• LASR Documentation
• Issue Tracker