v.out.ascii - GRASS GIS manual
Author: GRASS Development Team
Description: v.out.ascii: By default only features with category are exported. To export all features use 'layer=-1'.
Keywords: vector, export, output, ASCII

## NAME

v.out.ascii - Exports a vector map to a GRASS ASCII vector representation.
By default only features with category are exported. To export all features use 'layer=-1'.

## KEYWORDS

vector, export, output, ASCII

## SYNOPSIS

v.out.ascii
v.out.ascii --help
v.out.ascii [-ocr] input=name [layer=string] [type=string[,string,...]] [output=name] [columns=name[,name,...]] [cats=range] [where=sql_query] format=string [separator=character] [precision=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-o
  Create old (version 4) ASCII file
-c
  Include column names in output (points mode)
-r
  Only export points falling within current 3D region (points mode)
--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 vector map
  Or data source for direct OGR access
layer=string
  Layer number or name ('-1' for all layers)
  A single vector map can be connected to multiple database tables. This number determines which table to use. When used with direct OGR access this is the layer name.
  Default: 1
type=string[,string,...]
  Input feature type
  Options: point, line, boundary, centroid, area, face, kernel
  Default: point,line,boundary,centroid,area,face,kernel
output=name
  Name for output ASCII file or ASCII vector name if '-o' is defined
  If not given or '-' then standard output
columns=name[,name,...]
  Name of attribute column(s) to be exported (point mode)
  "*" for all columns
cats=range
  Category values
  Example: 1,3,7-9,13
where=sql_query
  WHERE conditions of SQL statement without 'where' keyword
  Example: income < 1000 and population >= 10000
format=string [required]
  Output format
  Options: point, standard, wkt
  Default: point
  point: Simple point format (point per row)
  standard: GRASS ASCII vector format
  wkt: OGC well-known text
separator=character
  Field separator
  Field separator (points mode)
  Default: pipe
precision=integer
  Number of significant digits (floating point only)
  Options: 0-32
  Default: 8

## DESCRIPTION

v.out.ascii converts a GRASS vector map in binary format to a GRASS vector map in ASCII format. Using flag -o v.out.ascii output will be in old (version 4) ASCII format.

If the output parameter is not given then the data is sent to standard output.

## NOTES

The v.in.ascii module performs the function of v.out.ascii in reverse; i.e. it converts vector maps in ASCII format to their binary format. These two companion modules are useful both for importing and exporting vector maps between GRASS and other software, and for transferring data between machines.

If old version is requested, the output files from v.out.ascii is placed in the `$LOCATION/$MAPSET/dig_ascii/` and `$LOCATION/$MAPSET/dig_att` directory.

If layer > 0 then only features with a category number will be exported. Use v.category to add them if needed or define layer=-1 to export also features without category.

v.out.ascii in the old version mode (-o) does not copy the `dig_cats` file associated with the binary vector input map to the new output file name. The user must copy the `dig_cats` file to the new output name if this is desired (e.g. using the UNIX cp command).

It is possible to output the coordinates of vertices in a non-points vector feature by first converting the vector feature to a points map with v.to.points and then exporting with v.out.ascii in points mode.

## EXAMPLES

### Standard mode

See ASCII format specification.

    v.out.ascii input=quads format=standard

    ORGANIZATION: US Army Const. Eng. Rsch. Lab
    DIGIT DATE:   May 1987
    DIGIT NAME:   grass
    MAP NAME:     Quads
    MAP DATE:     May 1987
    MAP SCALE:    24000
    OTHER INFO:
    ZONE:         13
    MAP THRESH:   18.288000
    VERTI:
    B  4
     599587.1820962 4914067.53414294
     589639.15126831 4913922.5687301
     589440.96838162 4927803.62500018
     599375.87959179 4927959.83330436
    B  2
     599375.87959179 4927959.83330436
     599587.1820962 4914067.53414294
    B  4
     599587.1820962 4914067.53414294
     609541.5508239 4914236.0597482
     609316.10665227 4928116.8490555
     599375.87959179 4927959.83330436
    C  1 1
     594125.63    4921115.58
     1     1
    C  1 1
     604433.84    4921087.1
     1     2

### Point mode

    v.out.ascii input=quads format=point

    594125.63|4921115.58|1
    604433.84|4921087.1|2

Print also selected attributes:

    v.out.ascii input=geodetic_pts format=point where="cat > 5 and cat <= 8" columns=GEOD_NAME

    573638.06289275|271623.25042595|6|27 WC 6
    574416.81289275|274116.65542595|7|27 WC 7
    575301.31189275|275303.81342595|8|27 WC 8

To print all attributes type columns=*:

    v.out.ascii input=geodetic_pts format=point where="cat > 5 and cat <= 8" columns=*
    573638.06289275|271623.25042595|6|6|0.00000000|0.00000000|6|6|27 WC 6|573638.09200000|271623.24100000|0.00|0|1.00000000|1.00000000
    574416.81289275|274116.65542595|7|7|0.00000000|0.00000000|7|7|27 WC 7|574416.84100000|274116.64900000|0.00|0|1.00000000|1.00000000
    575301.31189275|275303.81342595|8|8|0.00000000|0.00000000|8|8|27 WC 8|575301.30600000|275303.82600000|0.00|0|1.00000000|1.00000000

### WKT mode

WKT is abbreviation for Well-known text.

    v.out.ascii input=quads format=wkt

    POLYGON((599587.18209620 4914067.53414294, 589639.15126831 4913922.56873010,
             589440.96838162 4927803.62500018, 599375.87959179 4927959.83330436,
             599587.18209620 4914067.53414294))
    POLYGON((599587.18209620 4914067.53414294, 599375.87959179 4927959.83330436,
             609316.10665227 4928116.84905550, 609541.55082390 4914236.05974820,
             599587.18209620 4914067.53414294))

## SEE ALSO

v.category, v.in.ascii, v.to.points

GRASS ASCII vector format specification
GRASS SQL interface

## AUTHORS

Michael Higgins, U.S. Army Construction Engineering Research Laboratory
James Westervelt, U.S. Army Construction Engineering Research Laboratory
Radim Blazek, ITC-Irst, Trento, Italy
Attribute selection added by Martin Landa, Czech Technical University in Prague, Czech Republic (2008/12)

## SOURCE CODE

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

Accessed: Sunday Jun 28 03:49:40 2026

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