The input is read from a file specified by input option or from standard input.
Field separator may be a character, the word 'tab' (or '\t') for tab, or 'space' (or ' ') for blank.
The v.out.ascii GRASS module performs the function of v.in.ascii in reverse; i.e., it converts vector files in binary format to ASCII format. These two companion programs are useful both for importing and exporting vector files between GRASS and other software, and for transferring data between machines.
A GRASS ASCII vector file (in standard mode) may contain a mix of primitives including points, lines, boundaries, centroids, areas, faces, and kernels. On top a header can be defined (see example below).
The primitive codes are as follows:
Import of files without category ID column
If the input file does not contain any vector ID column,
there is the possibility to auto-generate these IDs (categories).
To automatically add an additional column named 'cat', the
cat parameter must be set to the virtual column number 0
(cat=0). This is the default action if the cat parameter
is not set.
Importing from a spreadsheet
Data may be imported from many spreadsheet programs by saving the
spreadsheet as a comma separated variable (.csv) text file, and then
using the fs=',' option with v.in.ascii in points mode.
If the input file contains any header lines, such as column headings, the
skip parameter should be used. These skipped header lines will be
written to the map's history file for later reference (read with
v.info -h).
Any line starting with the hash character ('#') will be treated as a comment and skipped completely if located in the main data file. If located in the header, as defined by the skip parameter, it will be treated as a header line and written to the history file.
ORGANIZATION: GRASS Development Team
DIGIT DATE: 1/9/2005
DIGIT NAME: -
MAP NAME: test
MAP DATE: 2005
MAP SCALE: 10000
OTHER INFO: Test polygons
ZONE: 0
MAP THRESH: 0.500000
VERTI:
B 6 1
5958812.48844435 3400828.84221011
5958957.29887089 3400877.11235229
5959021.65906046 3400930.7458436
5959048.47580612 3400973.65263665
5959069.92920264 3401032.64947709
5958812.48844435 3400828.84221011
1 1
B 4 1
5959010.9323622 3401338.36037757
5959096.7459483 3401370.54047235
5959091.38259917 3401450.99070932
5959010.9323622 3401338.36037757
1 2
Example 1b) - standard mode
Sample ASCII 3D line vector map for 'standard' mode with simplified input
(no header). The example can be tested in the Spearfish sample dataset:
echo "L 5 1 591336 4927369 1224 594317 4925341 1292 599356 4925162 1469 602396 4926653 1235 607524 4925431 1216 1 321 " | v.in.ascii -zn out=line3d format=standardThis can be used to create a vector line of a GPS track: the GPS points have to be stored into a file with a preceding 'L' and the number of points (per line).
Example 2
Generate a 2D points vector file 'coords.txt' as ASCII file:
1664619|5103481 1664473|5095782 1664273|5101919 1663427|5105234 1663709|5102614
Import into GRASS:
v.in.ascii input=coords.txt output=mymapAs the cat option is set to 0 by default, an extra column 'cat' containing the IDs will be auto-generated.
Example 3
Generate a 2D points vector file 'points.dat' as ASCII file:
1|1664619|5103481|studna 2|1664473|5095782|kadibudka 3|1664273|5101919|hruska 4|1663427|5105234|mysi dira 5|1663709|5102614|mineralni pramen
Import into GRASS:
cat points.dat | v.in.ascii out=mypoints x=2 y=3 cat=1 \
columns='cat int, x double, y double, label varchar(20)'
The module is reading from standard input, using the default '|' (pipe) delimiter.
Example 4
Generating a 3D points vector map from DBMS (idcol must be an integer column):
echo "select east,north,elev,idcol from mytable" | db.select -c | v.in.ascii -z out=mymapThe module is reading from standard input, using the default '|' (pipe) delimiter.
Example 5
Generate a 3D points vector file 'points3d.dat' with attributes as ASCII file:
593493.1|4914730.2|123.1|studna|well 591950.2|4923000.5|222.3|kadibudka|closet 589860.5|4922000.0|232.3|hruska|pear 590400.5|4922820.8|143.2|mysi dira|mouse hole 593549.3|4925500.7|442.6|mineralni pramen|mineral spring 600375.7|4925235.6|342.2|kozi stezka|goat path
Import into GRASS:
#As the cat option is set to 0 by default, an extra column 'cat'
#containing the IDs will be auto-generated (no need to define that):
cat points3d.dat | v.in.ascii -z z=3 cat=0 out=mypoints3D \
columns='x double, y double, z double, label_cz varchar(20), label_en varchar(20)'
v.info -c mypoints3D
v.info mypoints3D
Example 6
Generate points file by clicking onto the map:
#For LatLong locations:
d.where -d -l | awk '{printf "%f|%f|point\n", $1, $2}' | v.in.ascii out=points \
columns='x double, y double, label varchar(20)'
#For other projections:
d.where | awk '{printf "%f|%f|point\n", $1, $2}' | v.in.ascii out=points \
columns='x double, y double, label varchar(20)'
The 'point' string (or some similar entry) is required to generate a database table.
When simply piping the coordinates (and optionally height) without additional column(s)
into v.in.ascii, only the vector map geometry will be generated.
Example 7
Convert ground control points from i.points into vector points:
cat $MAPSET/group/$GROUP/POINTS | v.in.ascii out=$GROUP_gcp fs=space skip=3 \
col='x double, y double, x_target double, y_target double, ok int'
Last changed: $Date$