dhm-densitycheck

Tool to check point density of point cloud deliverables.

Installation

An appropriate conda environment (here named densitycheck) can be created with:

conda env create -n densitycheck -f environment.yml

The following assumes that this environment is activated.

The tool supports editable installation using pip. To install it this way, use the following command in the root directory:

pip install -e .

You may want to test your installation by calling pytest in the root directory.

Usage

The tool is intended to be used on a single pointcloud tile, producing a raster of point densities with density (points per georeferenced area unit) reported per raster cell. The spatial extent is automatically computed. The command to use is:

point_density [-h] [--cell-size CELL_SIZE] [--returns {ALL,FIRST,LAST}] [--include INCLUDE] [--exclude EXCLUDE] [--print-stats] input_las output_raster

Parameter	Description
input_las	Path to laspy-readable pointcloud file (LAS, LAZ, COPC)
output_raster	Path to desired output raster file. Will be written as COG (Cloud-Optimized GeoTIFF)
--cell-size CELL_SIZE	Size of cells in output raster in georeferenced units (commonly meters). Default: 1.0
--returns {ALL,FIRST,LAST}	Consider only points with these return numbers. Note that some pointcloud software regards "only" returns as distinct from "first" and "last" returns, which is not the case here (i.e., "only" returns count both as "first" and "last" with this tool).
--include INCLUDE	Optional inclusion mask, intended for enforcing a particular tile footprint. Must be an OGR-readable datasource with a single layer
--exclude EXCLUDE	Optional exclusion mask for lakes etc. Must be an OGR-readable datasource with a single layer
--print-stats	Print density statistics to standard output. Will be formatted as a JSON object
-h	Print help and exit

Example

This will create a COG raster with 10-meter cells, containing number of points per square meter in each cell:

point_density 1km_1234_567.laz 1km_1234_567_density.tif --cell-size 10.0 --exclude dk_lakes.gpkg

Same, but with an inclusion mask to delimit tile footprint:

point_density 1km_1234_567.laz 1km_1234_567_density.tif --cell-size 10.0 --include 1km_1234_567_tile.gpkg --exclude dk_lakes.gpkg

Same, but with output statistics printed to stdout and redirected to a text file:

point_density 1km_1234_567.laz 1km_1234_567_density.tif --cell-size 10.0 --include 1km_1234_567_tile.gpkg --exclude dk_lakes.gpkg --print-stats > 1km_1234_567_stats.txt