--- name: "r3.out.ascii" section: "1grass" platform: "linux" package: "grass-doc" version: "8.4.1-1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/r3.out.ascii" --- # r3.out.ascii(1grass) Converts a 3D raster map layer into a ASCII text file. ## 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: integer ``` The **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) . . . . . . . . . (x, y, z + depths) (x + 1, y, z + depths) ... (x + cols, y, z + depths) ``` This order is compatible with the *r.in.ascii* row -\> column ordering. 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: Monday Feb 24 17:51:08 2025 Main index \| 3D raster index \| Topics index \| Keywords index \| Graphical index \| Full index © 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual