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NAME

       r3.out.ascii  - Converts a 3D raster map layer into a ASCII text file.

KEYWORDS

       raster3d, export, 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".

Example

       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

       Last changed: $Date: 2015-01-21 04:31:26 +0100 (Wed, 21 Jan 2015) $

SOURCE CODE

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

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