NAME

v.out.lidar - Exports vector points as LAS point cloud
Converts LAS LiDAR point clouds to a GRASS vector map with libLAS

KEYWORDS

vector, export, output, LIDAR, points

SYNOPSIS

v.out.lidar
v.out.lidar --help
v.out.lidar [-rw] input=name [layer=string] output=name [cats=range] [where=sql_query] [id_layer=string] [return_layer=string] [class_layer=string] [rgb_layer=string] [return_column=name] [n_returns_column=name] [class_column=name] [rgb_column=name] [red_column=name] [green_column=name] [blue_column=name] las_xyscale=float las_zscale=float [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-r: Limit export to the current region
-w: Ignore color table
Ignore color table even when set and not other options are present
--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]: Name of input vector map
Or data source for direct OGR access
layer=string: Layer number or name (’-1’ for all layers)
A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
Default: -1
output=name [required]: Name for output file
cats=range: Category values
Example: 1,3,7-9,13
where=sql_query: WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and population >= 10000
id_layer=string: Layer number to store generated point ID as category
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
return_layer=string: Layer number to store return number as category
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
class_layer=string: Layer number to store class number as category
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
rgb_layer=string: Layer number where RGB color is stored as category
Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
return_column=name: Column with return number
Name of attribute column
n_returns_column=name: Column with return number
Name of attribute column
class_column=name: Column with return number
Name of attribute column
rgb_column=name: RGB color definition column
Color definition in R:G:B form
red_column=name: Column with red color
Name of attribute column
green_column=name: Column with green color
Name of attribute column
blue_column=name: Column with blue color
Name of attribute column
las_xyscale=float [required]: Internal scale to apply to X and Y values
This scale does not change the values itself but only how precisely they are stored, for example 0.01 will preserve two decimal places
Default: 0.01
las_zscale=float [required]: Internal scale to apply to z values
This scale does not change the values itself but only how precisely they are stored, for example 0.01 will preserve two decimal places
Default: 0.01

DESCRIPTION

v.out.lidar converts GRASS vector map to a LiDAR point clouds in LAS format using the libLAS library.

The -r flag limits the export to the current computational region extent (see g.region). The where option limits the export by attributes (applied only when the columns are used for export).

LAS format stores the coordinates as integers rounding the decimal places. Before that a scale is applied to preserve a certain number of decimal places. This scale can be set using las_xyscale and las_xscale options. For example, the scale value 0.01 will preserve two decimal places while the value 1.0 will preserve none.

NOTES

The typical file extensions for the LAS format are .las and .laz (compressed). The compressed LAS (.laz) format can be exported only if libLAS has been compiled with LASzip support. It is also good when libLAS was compiled with GDAL. This is needed when working with projections.

EXAMPLE

Generate fractal surface and export is as point in LAS format:


g.region raster=elevation res=100
r.surf.fractal output=fractals
r.to.vect input=fractals output=fractals type=point -z
v.out.lidar input=fractals output=fractals.las

REFERENCES

ASPRS LAS format
LAS library

AUTHOR

Vaclav Petras

SOURCE CODE

Available at: v.out.lidar source code (history)