table of contents
r3.out.ascii(1grass) | GRASS GIS User's Manual | r3.out.ascii(1grass) |
NAME¶
r3.out.ascii - Converts a 3D raster map layer into a ASCII text file.
KEYWORDS¶
raster3d, export, output, voxel, conversion, ASCII
SYNOPSIS¶
r3.out.ascii
r3.out.ascii --help
r3.out.ascii [-hrdcm] input=string
[output=name] [precision=integer]
[null_value=string] [--overwrite] [--help]
[--verbose] [--quiet] [--ui]
Flags:¶
- -h
-
Suppress printing of header information - -r
-
Switch the row order in output from north->south to south->north - -d
-
Switch the depth order in output from bottom->top to top->bottom - -c
-
Print grass6 compatible format. Flags -d and -r are ignored. - -m
-
Use 3D raster mask (if exists) with input map - --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=string [required]
-
3D raster map to be converted to ASCII - output=name
-
Name for ASCII output file - precision=integer
-
Number of decimal places for floats
Options: 0-20
Default: 8 - null_value=string
-
String representing NULL value
Default: *
DESCRIPTION¶
r3.out.ascii exports a 3D raster map in ASCII format. The input parameter is a valid 3D raster map in the current mapset search path. The output parameter is the name of an ASCII file which will be written in the current working directory.
If output is not specified then standard output (stdout) is used. The -h flag may be used to suppress header information. The module is sensitive to region settings (set with g.region).
The -c flag will create GRASS 6 r3.in.ascii compatible output.
NOTES¶
The default format of the exported ASCII file is equivalent to that required by r3.in.ascii. In particular, files output by r3.out.ascii with header information may be converted back to 3D raster maps with r3.in.ascii.
The format of the ASCII file is:
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: integerThe version and order options have been introduced in GRASS 7 in June 2011. The order option describes the order of rows and depths in the output. It is possible to create output of different row order using the -r flag and output of different depths order using the -d flag. The default order is:
west -> east for columns north -> south for rows bottom -> top for depths
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. Cell
values are exported as a series of horizontal slices in row-major order. The
data starts with the upper left corner (NW) at the bottom of the data set.
The values at the following coordinates are exported:
(x, y + rows, z) (x + 1, y + rows, z) ... (x + cols, y + rows, z) (x, y + rows, z) (x + 1, y + rows - 1, z) ... (x + cols, y + rows - 1, z)This order is compatible with the r.in.ascii row -> column ordering.
. . .
. . .
. . . (x, y, z + depths) (x + 1, y, z + depths) ... (x + cols, y, z + depths)
Supported orders are:
- nsbt: north -> south and bottom -> top ordering which is the default (no flags)
- snbt: south -> north and bottom -> top ordering using -r flag
- nstb: north -> south and top -> bottom ordering using -d flag
- sntb: south -> north and top -> bottom ordering using -rd flag
The internal storage scheme of 3D raster maps is visualized in the
following picture:
The coordinate system and tile layout of a voxel map in GRASS |
One level maps can be imported with r.in.ascii (2D raster) using the default nsbt order and removing the header lines "version", "order", "top", "bottom" and "levels".
EXAMPLES¶
We define a small region with 4 columns, 3 rows and 2 depths
(4x3x2) and export it using different ordering definitions:
g.region res3=1 t=2 b=0 w=0 e=4 s=0 n=3 r3.mapcalc "simple_example = row() + col() + depth()"
Default order:
r3.out.ascii input=simple_example dp=0 version: grass7 order: nsbt north: 3.000000 south: 0.000000 east: 4.000000 west: 0.000000 top: 2.000000 bottom: 0.000000 rows: 3 cols: 4 levels: 2 3 4 5 6 4 5 6 7 5 6 7 8 4 5 6 7 5 6 7 8 6 7 8 9
Inverse row order (-r)
r3.out.ascii input=simple_example dp=0 -r version: grass7 order: snbt north: 3.000000 south: 0.000000 east: 4.000000 west: 0.000000 top: 2.000000 bottom: 0.000000 rows: 3 cols: 4 levels: 2 5 6 7 8 4 5 6 7 3 4 5 6 6 7 8 9 5 6 7 8 4 5 6 7
Inverse depth order (-d)
r3.out.ascii input=simple_example dp=0 -d version: grass7 order: nstb north: 3.000000 south: 0.000000 east: 4.000000 west: 0.000000 top: 2.000000 bottom: 0.000000 rows: 3 cols: 4 levels: 2 4 5 6 7 5 6 7 8 6 7 8 9 3 4 5 6 4 5 6 7 5 6 7 8
Inverse row and depth order (-rd)
r3.out.ascii input=simple_example dp=0 -rd version: grass7 order: sntb north: 3.000000 south: 0.000000 east: 4.000000 west: 0.000000 top: 2.000000 bottom: 0.000000 rows: 3 cols: 4 levels: 2 6 7 8 9 5 6 7 8 4 5 6 7 5 6 7 8 4 5 6 7 3 4 5 6
SEE ALSO¶
r3.in.ascii, r.out.ascii, g.region
AUTHORS¶
Roman Waupotitsch, Michael Shapiro, Helena Mitasova, Bill Brown, Lubos Mitas, Jaro Hofierka, Sören Gebbert
SOURCE CODE¶
Available at: r3.out.ascii source code (history)
Accessed: Thursday Aug 01 05:16:41 2024
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