GRASS GIS manual: v.proj

Note: This document is for an older version of GRASS GIS that is outdated. You should upgrade, and read the current manual page.

NAME

v.proj - Re-projects a vector map from one location to the current location.

KEYWORDS

vector, projection, transformation

SYNOPSIS

v.proj
v.proj help
v.proj [-lz] [input=name] location=name [mapset=name] [dbase=path] [output=name] [--overwrite] [--verbose] [--quiet]

Flags:

-l: List vector maps in input location and exit
-z: Assume z co-ordinate is ellipsoidal height and transform if possible; 3D vector maps only
--overwrite: Allow output files to overwrite existing files
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

input=name: Name of input vector map
location=name: Location containing input vector map
mapset=name: Mapset containing input vector map
dbase=path: Path to GRASS database of input location
output=name: Name for output vector map (default: input)

DESCRIPTION

v.proj allows a user to convert a vector map in a specified mapset of a specified location (different from current) with projection of input location to the vector map in a current mapset of current location with projection of current location (both projections are defined by corresponding PROJ_INFO files). The projection information is taken from the current PROJ_INFO files, as set and viewed with g.proj.

NOTES

If output is not specified it is set to be the same as input map name.
If mapset is not specified, its name is assumed to be the same as the current mapset's name.
If dbase is not specified it is assumed to be the current database. The user only has to specify dbase if the source location is stored in another separate GRASS database.

v.proj supports general datum transformations, making use of the PROJ.4 co-ordinate system translation library.

In order to preserve spatial detail, it is recommended to densify linear features with v.split before reprojecting. Depending on the source and target CRS (Coordinate Reference System), geometries can be substantially deformed (straight lines become curves, squares become trapezoids, etc). In these cases densification of linear features can help to avoid topological errors.

EXAMPLES

v.proj in=mymap location=latlong mapset=user1

REFERENCES

PROJ 4: Projection/datum support library.

Further reading

AUTHORS

Irina Kosinovsky, US ARMY CERL
M.L. Holko, USDA, SCS, NHQ-CGIS
R.L. Glenn, USDA, SCS, NHQ-CGIS

Last changed: $Date: 2014-01-13 01:31:54 -0800 (Mon, 13 Jan 2014) $

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