NAME¶
v.out.ascii - Converts a GRASS binary vector map to a GRASS ASCII
vector map.
KEYWORDS¶
vector, export
SYNOPSIS¶
v.out.ascii
v.out.ascii help
v.out.ascii [-
or]
input=
name
[
output=
name] [
format=
string]
[
fs=
character] [
dp=
integer]
[
layer=
integer] [
columns=
name[,
name,...]]
[
where=
sql_query] [--
verbose] [--
quiet]
Flags:¶
- -o
-
Create old (version 4) ASCII file
- -r
-
Only export points falling within current 3D region (points mode)
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- input=name
-
Name of input vector map
- output=name
-
Path to resulting ASCII file or ASCII vector name if '-o' is defined
- format=string
-
Output format
Options: point,standard
Default: point
- fs=character
-
Field separator (points mode)
Default: |
- dp=integer
-
Number of significant digits (floating point only)
Options: 0-32
Default: 8
- layer=integer
-
Layer number
A single vector map can be connected to multiple database tables. This
number determines which table to use.
Default: 1
- columns=name[,name,...]
-
Name of attribute column(s) to be exported (point mode)
- where=sql_query
-
WHERE conditions of SQL statement without 'where' keyword
Example: income = 10000
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 coordinates of any
point data within the vector map is sent to stdout.
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 module are useful both for importing and exporting vector
maps between GRASS and other software, and for transferring data between
machines.
If the
format parameter is set to
standard, a GRASS ASCII vector
map will be exported, which may contain a mix of primitives including points,
lines, boundaries, centroids, areas, faces, and kernels. The beginning of the
output ascii file will contain a header listing any metadata for the input
vector map, if such metadata exists. An example of the
standard format
is given below.
The header is similar as the head file of vector binary format but contains
bounding box also. Key words are:
ORGANIZATION
DIGIT DATE
DIGIT NAME
MAP NAME
MAP DATE
MAP SCALE
OTHER INFO
ZONE
WEST EDGE
EAST EDGE
SOUTH EDGE
NORTH EDGE
MAP THRESH
The body begins with the row:
VERTI:
followed by records of primitives:
TYPE NUMBER_OF_COORDINATES [NUMBER_OF_CATEGORIES]
X Y [Z]
X Y [Z]
[ LAYER CATEGORY]
[ LAYER CATEGORY]
Everything above in [ ] is optional.
The primitive codes are as follows:
- ’P': point
- ’L': line
- ’B': boundary
- ’C': centroid
- ’F': face (3D boundary)
- ’K': kernel (3D centroid)
- ’A': area (boundary) - better use 'B'; kept only for
backward compatibility
The coordinates are listed following the initial line containing the primitive
code, the total number of vectors in the series, and (optionally) the number
of categories (1 for a single layer, higher for multiple layers). Below that 1
or several lines follow to indicate the layer number and the category number
(ID).
The order of coordinates is
X Y [Z]
In pre-GRASS 6 versions of the ASCII file, the order of coordinates is:
Y X
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.
Only features with a category number will be exported. Use
v.category to
add them if needed.
v.out.ascii 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¶
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
v.out.ascii input=archsites format=point where="cat > 5 and cat <=
8" columns=str1
600375|4925235|6|Prairie Site
606635|4920773|7|Jensen Pass
595755|4925300|8|No Name
SEE ALSO¶
v.category, v.in.ascii, v.to.points
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, CTU in Prague, Czech Republic
(2008/12)
Last changed: $Date: 2011-11-08 10:42:51 +0100 (Tue, 08 Nov 2011) $
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