v.in.mapgen - GRASS manual
Author: GRASS Development Team
Description: v.in.mapgen: Imports Mapgen or Matlab-ASCII vector maps into GRASS.
Keywords: vector, import

## NAME

v.in.mapgen - Imports Mapgen or Matlab-ASCII vector maps into GRASS.

## KEYWORDS

vector, import

## SYNOPSIS

v.in.mapgen
v.in.mapgen --help
v.in.mapgen [-fz] input=name [output=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-f
  Input map is in Matlab format
-z
  Create a 3D vector points map from 3 column Matlab data
--overwrite
  Allow output files to overwrite existing files
--help
  Print usage summary
--verbose
  Verbose module output
--quiet
  Quiet module output
--ui
  Force launching GUI dialog

### Parameters:

input=name [required]
  Name of input file in Mapgen/Matlab format
output=name
  Name for output vector map (omit for display to stdout)

## DESCRIPTION

v.in.mapgen allows the user to import Mapgen or Matlab vector maps into GRASS.

## NOTES

This module only imports data into vector lines.

The user can get coastline data in Mapgen or Matlab format from NOAA's Coastline Extractor at https://www.ngdc.noaa.gov/mgg/shorelines/shorelines.html.

Matlab vector line maps are simply a series of "x y" data points. Lines are separated by a row containing `NaN NaN`. Output from Matlab with this command:

        save filename.txt arrayname -ASCII

The user can import 3D lines from Matlab by exporting a 3 column array and using the -z flag.

## SEE ALSO

v.in.ascii

## AUTHORS

Based on v.in.mapgen.sh for GRASS 5.0 by Andreas Lange
Rewritten for GRASS 6 by Hamish Bowman

## SOURCE CODE

Available at: v.in.mapgen source code (history)

Accessed: Monday May 11 17:55:46 2026

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