v.out.ascii.1grass man page

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’.


vector, export, 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]



Create old (version 4) ASCII file


Include column names in output (points mode)


Only export points falling within current 3D region (points mode)


Allow output files to overwrite existing files


Print usage summary


Verbose module output


Quiet module output


Force launching GUI dialog


input=name [required]

Name of input vector map
Or data source for direct OGR access


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


Input feature type
Options: point, line, boundary, centroid, area, face, kernel
Default: point,line,boundary,centroid,area,face,kernel


Name for output ASCII file or ASCII vector name if ’-o’ is defined
If not given or ’-’ then standard output


Name of attribute column(s) to be exported (point mode)
"*" for all columns


Category values
Example: 1,3,7-9,13


WHERE conditions of SQL statement without ’where’ keyword
Example: income < 1000 and inhab >= 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


Field separator
Field separator (points mode)
Default: pipe


Number of significant digits (floating point only)
Options: 0-32
Default: 8


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.


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.


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
ZONE:         13
MAP THRESH:   18.288000
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

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


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)

Last changed: $Date: 2014-07-29 00:07:11 +0200 (Tue, 29 Jul 2014) $

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