r3.in.xyz(1)

NAME
r3.in.xyz.py - Create a 3D raster map from an assemblage of many coordinates using univariate statistics

KEYWORDS
raster3d, import, voxel, LIDAR, statistics, conversion, aggregation, binning

SYNOPSIS
r3.in.xyz.py
r3.in.xyz.py --help
r3.in.xyz.py [-sgi] input=name output=name [method=string] [type=string] [separator=character] [x=integer] [y=integer] [z=integer] [value_column=integer] [vrange=min,max] [vscale=float] [percent=integer] [pth=integer] [trim=float] [workers=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

  Flags:

-s
    Scan data file for extent then exit

-g
    In scan mode, print using shell script style

-i
    Ignore broken lines

--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]
    ASCII file containing input data

output=name [required]
    Name for output raster map

method=string
    Statistic to use for raster values
    Options: n, min, max, range, sum, mean, stddev, variance, coeff_var, median, percentile, skewness, trimmean
    Default: mean

type=string
    Storage type for resultant raster map
    Options: float, double
    Default: float

separator=character
    Field separator
    Special characters: pipe, comma, space, tab, newline
    Default: pipe

x=integer
    Column number of x coordinates in input file (first column is 1)
    Default: 1

y=integer
    Column number of y coordinates in input file
    Default: 2

z=integer
    Column number of z coordinates in input file
    Default: 3

value_column=integer
    Column number of data values in input file
    If not given or set to 0, the data points’ z-values are used
    Default: 0

vrange=min,max
    Filter range for value column data (min,max)

vscale=float
    Scaling factor to apply to value column data
    Default: 1.0

percent=integer
    Percent of map to keep in memory
    Options: 1-100
    Default: 100

pth=integer
    pth percentile of the values
    Options: 1-100

trim=float
    Discard <trim> percent of the smallest and <trim> percent of the largest observations
    Options: 0-50

workers=integer
    Number of parallel processes to launch
    Options: 1-256
    Default: 1

DESCRIPTION
r3.in.xyz imports sparse XYZ data from an ASCII file into a 3D raster map (voxels). It does this by running the r.in.xyz module multiple times for different z-ranges and then assembling the slices with r.to.rast3.

See the r.in.xyz help page for general parameter usage and tips.

The map is created using the rows, columns, and depths set by current region settings. Be sure to check and adjust these with the g.region module before performing the import.

You may either use the z-value as the data value for the voxel (e.g. with the ’n’ statistic), or alternately scan another column for the data values to bin into the voxels. This alternate data column can be both filtered by range and have a scaling factor applied to it.

NOTES
The 2D and 3D horizontal region resolutions must match. See the EXAMPLES section below.

Unlike r.in.xyz, reading from stdin and z-scaling are not possible. Filtering by z-range is accomplished by setting the 3D region.

To enable parallel processing support, set the workers= option to match the number of CPUs or CPU-cores available on your system. Alternatively, the WORKERS environment variable can be set to the number of concurrent processes desired.

Points falling exactly on a vertical bound will belong to the depth band below them, except for points exactly on the top bound, which will belong to the top-most slice.

The script is expected to be nearly as efficient as if it was fully written in C.

EXAMPLE
Using the Serpent Mound dataset. (see the GRASS LiDAR wiki page)

  #scan dataset for extent:
  r3.in.xyz -s in=Serpent_Mound_Model_LAS_Data.txt out=dummy \
     x=1 y=2 z=3 separator=space
  # set the 2D and 3D regions:
  g.region n=4323641.57 s=4320942.61 w=289020.90 e=290106.02 res=1 -a
  g.region b=166 t=216 res3=1 tbres=5 -3 -p
  r3.in.xyz in=Serpent_Mound_Model_LAS_Data.txt out=serpent3D \
     method=mean x=1 y=2 z=3 separator=space type=float

The same, but aggregate and store backscatter strength from column 5 into voxels in instead of the z-value:

  r3.in.xyz in=Serpent_Mound_Model_LAS_Data.txt out=serpent3D.bakscat \
     method=mean x=1 y=2 z=3 val=5 separator=space type=float

KNOWN ISSUES
r.to.rast3 always creates a double output map regardless of input.

SEE ALSO
g.region, r.in.xyz, r.to.rast3

AUTHOR
Hamish Bowman
Dunedin, New Zealand

SOURCE CODE

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

Accessed: Friday Jul 14 13:18:53 2023

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