GRASS GIS manual: r3.in.lidar

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.6, available here.
Updated manual page: here

NAME

r3.in.lidar - Creates a 3D raster map from LAS LiDAR points

KEYWORDS

3D raster, import, LIDAR

SYNOPSIS

r3.in.lidar

r3.in.lidar --help

r3.in.lidar [-dv] input=name n=name sum=name mean=name proportional_n=name proportional_sum=name [return_filter=string] [class_filter=integer[,integer,...]] [base_raster=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-d: Use base raster actual resolution instead of computational region
-v: Use only valid points; Points invalid according to APSRS LAS specification will be filtered out
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

input=name [required]: LAS input file; LiDAR input file in LAS format (*.las or *.laz)
n=name [required]: Count of points per cell; Name for output 3D raster map
sum=name [required]: Sum of values of point intensities per cell; Name for output 3D raster map
mean=name [required]: Mean of point intensities per cell; Name for output 3D raster map
proportional_n=name [required]: 3D raster map of proportional point count; Point count per 3D cell divided by point count per vertical column
proportional_sum=name [required]: 3D raster map of proportional sum of values; Sum of values per 3D cell divided by sum of values per vertical column
return_filter=string: Only import points of selected return type; If not specified, all points are imported; Options: first, last, mid
class_filter=integer[,integer,...]: Only import points of selected class(es); Input is comma separated integers. If not specified, all points are imported.
base_raster=name: Subtract raster values from the z coordinates; The scale for z is applied beforehand, the filter afterwards

DESCRIPTION
NOTES
EXAMPLES
- Point density vertical structure reduced to the terrain
SEE ALSO
REFERENCES
AUTHOR

DESCRIPTION

Figure: Proportional count of points per 3D cell. When 50% of all points in a vertical column fall into a given 3D cell, the value is 0.5. Here, the green color was assigned to 0.5, red to 1 and yellow to 0. The figure shows vertical slices and green color indicates high vegetation while red color indicates bare ground.

NOTES

This module is highly experimental. Don't rely on its functionality or interface. Please report issues on the mailing list or in the bug tracker.
No projection check or reprojection is performed, make sure you are using data in the right projection for your GRASS Location.
Selection of points according to return or class is not yet supported.
All outputs are currently mandatory.
Some temporary maps are created but not cleaned up.
Expects points to have intensity (random result for related outputs when they don't).

EXAMPLES

Set the region according to a 2D raster and adding 3D minimum (bottom), maximum (top) and vertical (top-bottom) resolution.

g.region rast=secref b=80 t=160 tbres=5 -p3

Now, r3.in.lidar will create the 3D raster of the size given by the computation region:

r3.in.lidar input=points.las n=points_n sum=points_sum \
    mean=points_mean proportional_n=points_n_prop \
    proportional_sum=points_sum_prop

Point density vertical structure reduced to the terrain

Create ground raster:

r.in.lidar input=points.las output=ground method=mean class_filter=2

Set vertical extent of computational region to (relative) coordinates above ground:

g.region rast=secref b=0 t=47 -p3

Compute point density:

r3.in.lidar input=points.las n=points_n sum=points_sum \
    mean=points_mean proportional_n=points_n_prop \
    proportional_sum=points_sum_prop \
    base_raster=ground

REFERENCES

V. Petras, A. Petrasova, J. Jeziorska, H. Mitasova (2016): Processing UAV and lidar point clouds in GRASS GIS. XXIII ISPRS Congress 2016 [ISPRS Archives, ResearchGate]
ASPRS LAS format
LAS library
LAS library C API documentation

AUTHOR

Vaclav Petras, NCSU GeoForAll Lab

Last changed: $Date: 2016-08-22 19:07:22 -0700 (Mon, 22 Aug 2016) $

SOURCE CODE

Available at: r3.in.lidar source code (history)