v.in.ascii - Convert GRASS ascii file or points file to binary vector.

v.in.ascii

v.in.ascii help

v.in.ascii [-zte] [input=string] output=string [format=string] [fs=string] [columns=string] [x=integer] [y=integer] [z=integer] [cat=integer]

Flags:

Parameters:

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.

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.

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(2)'

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(2), label_en varchar(2)'

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|pointn", $1, $2}' | v.in.ascii out=points cat=0 columns='x double, y double, label varchar(2)'

#For other projections:

d.where | awk '{printf "%f|%f|pointn", $1, $2}' | v.in.ascii out=points cat=0 columns='x double, y double, label varchar(2)'

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.

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

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 $

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