r3.in.ascii(1)

NAME
r3.in.ascii - Converts a 3D ASCII raster text file into a (binary) 3D raster map.

KEYWORDS
raster3d, import, voxel, conversion, ASCII

SYNOPSIS
r3.in.ascii
r3.in.ascii --help
r3.in.ascii input=name output=name [null_value=string] [type=string] [precision=string] [compression=string] [tiledimension=XxYxZ] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

  Flags:

--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 file to be imported
    ’-’ for standard input

output=name [required]
    Name for output 3D raster map

null_value=string
    String representing NULL value data cell (use ’none’ if no such value)
    Default: *

type=string
    Data type used in the output raster3d map
    Options: default, double, float
    Default: default

precision=string
    Number of digits used as mantissa in the internal map storage, 0 -23 for float, 0 - 52 for double, max or default
    Default: default

compression=string
    The compression method used in the output raster3d map
    Options: default, zip, none
    Default: default

tiledimension=XxYxZ
    The dimensions of the tiles used in the output raster3d map (XxYxZ or default: 16x16x8)
    Default: default

DESCRIPTION
r3.in.ascii allows a user to create a (binary) GRASS 3D raster map layer from a 3D ASCII raster input file.

The tiledimension parameter defines the dimension of the tiles used in the output file. The format is: XxYxZ

The nv parameter specifies which value to convert to NULL-value. If the specified value is none, no conversion is performed. Default is none.

NOTES
The data is automatically imported into the correct internal coordinate system, that is visualized in the following picture, independently from the specified ordering in the ASCII input file:
The volume coordinate system and tile layout of the imported voxel map

  Format
The format of the 3D ASCII file:

version: "grass7"
order:   "nsbt" or "nstb" or "snbt" or "sntb"
north:   floating point
south:   floating point
east:    floating point
west:    floating point
top:     floating point
bottom:  floating point
rows:    integer
cols:    integer
levels:  integer

The version and order option have been introduced in GRASS 7 in June 2011. The version option is self explaining. The order option specifies the row and depth order of the data in the input file. The supported row/depth ordering is documented in the r3.out.ascii manual page. The order of the data in the input file does not specify the data order in the generated output 3D raster map which is in any case north -> south, west -> east, bottom -> top order. So dependent on the order information the data is automatically imported into the correct internal coordinate system.

The version and order options are not mandatory. In case no version and order option is specified, the default GRASS 6 ASCII format is assumed.

This header is followed by the cell values in floating point format organized in rows with constant col and level coordinate. The rows are organized by constant level coordinate. Individual cell values are separated by space or CR.

EXAMPLES
4x3x2 sample. Note in case no specific ordering is specified in the input file the upper-left (NW) corner of the bottom level comes first. The according order option is: nsbt for north -> south, bottom -> top ordering. This is identical with r.in.ascii for single level data. So the y coordinate is 0 at the northern edge. north: 3.0
south: 0.0
east: 4.0
west: 0.0
top: 2.0
bottom: 0.0
rows: 3
cols: 4
levels: 2
w111x1,y1,z1 w211x2,y1,z1 w311x3,y1,z1 w411x4,y1,z1
w121x1,y2,z1 w221x2,y2,z1 w321x3,y2,z1 w421x4,y2,z1
w131x1,y3,z1 w231x2,y3,z1 w331x3,y3,z1 w431x4,y3,z1
w112x1,y1,z2 w212x2,y1,z2 w312x3,y1,z2 w412x4,y1,z2
w122x1,y2,z2 w222x2,y2,z2 w322x3,y2,z2 w422x4,y2,z2
w132x1,y3,z2 w232x2,y3,z2 w332x3,y3,z2 w432x4,y3,z2

Note that unit tests for r3.in.ascii are implemented in the test.r3.out.ascii.sh script located in the r3.out.ascii directory.

EXAMPLES
Please refer to the detailed examples in r3.out.ascii.

SEE ALSO
r.in.ascii, r3.out.ascii, v.to.rast3, g.region

AUTHORS
Roman Waupotitsch, Michael Shapiro, Helena Mitasova, Bill Brown, Lubos Mitas, Jaro Hofierka, Sören Gebbert

SOURCE CODE

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

Latest change: Tuesday Feb 18 17:20:26 2025 in commit: 688e625e7db3be9a465ce99ba25f36d2ebdd5aeb

Main index | 3D raster index | Topics index | Keywords index | Graphical index | Full index

© 2003-2026 GRASS Development Team, GRASS 8.5.1dev Reference Manual