## DESCRIPTION

v.in.ascii converts a vector map in ASCII format to a vector map in binary format. The module may import two formats:

- standard contains all data types, each coordinate on one row
- point (default) reads only points, each point defined on one row. Values are separated by a user definable deliminator. If the 'columns' option is not defined, default names are used. It is possible to specify the column order for the x,y,z coordinates and category values.

The input is read from a file specified by input option or from standard input.

Field separator may be a character, '\t' for tabulator, ' ' for blank.

## NOTES

Use the -z flag to convert ASCII data into a 3D binary vector map.

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:

- 'B': boundary
- 'C': centroid
- 'L': line
- 'P': point
- 'F': face
- 'K': kernel
- '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 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]

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.

## EXAMPLES

Example 1
Sample ASCII polygon vector file for 'standard' mode. Note the blank before entering vertex coordinates:

           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

To create a vector line of a GPS track, in a similar way 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:

    cat coords.txt | v.in.ascii out=mymap

As 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=mymap

The module is reading from standard input, using the default '|' (pipe) delimiter.
The import works for 2D maps as well (no elev column and no '-z' flag).

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 cat 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 cat=0 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 cat=0 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.

The GRASS program v.out.ascii 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.

## SEE ALSO

db.execute, v.db.connect, v.info, v.out.ascii, v.build
v.build.polylines
SQL command notes for creating databases
Vector ASCII Format Specification

## 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

Last changed: $Date: 2005/08/04 08:30:11 $