NAME
v.proj - Re-projects a vector map from one project to the current project.
KEYWORDS
vector,
projection,
transformation,
import
SYNOPSIS
v.proj
v.proj --help
v.proj [-lzwb] project=name [mapset=name] [input=name] [dbase=path] [smax=float] [output=name] [pipeline=string] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
- -l
- List vector maps in input mapset and exit
- -z
- Assume z coordinate is ellipsoidal height and transform if possible
- 3D vector maps only
- -w
- Disable wrapping to -180,180 for latlon output
- Latlon output only, default is -180,180
- -b
- Do not build vector topology
- Recommended for massive point projection
- --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:
- project=name [required]
- Project (location) containing input vector map
- Project name (not path to project)
- mapset=name
- Mapset containing input vector map
- Default: name of current mapset
- input=name
- Name of input vector map to re-project
- dbase=path
- Path to GRASS database of input project
- Default: path to the current GRASS GIS database
- smax=float
- Maximum segment length in meters in output vector map
- Increases accuracy of reprojected shapes, disable with smax=0
- Default: 10000
- output=name
- Name for output vector map (default: input)
- pipeline=string
- PROJ pipeline for coordinate transformation
v.proj allows a user to convert a vector map in a specified mapset
of a specified project (different from current) with coordinate reference
system (CRS) of source project to the vector map in a current mapset of current
project with CRS of current project (both CRSs are defined in their
corresponding projects). The CRS information can be viewed and managed with
g.proj.
For an introduction to map CRSs (and the PROJ library), see the manual page of
r.proj.
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
project is stored in another separate GRASS database.
If
smax is set to
0 the automated vertex densification is
disabled (not recommended).
v.proj supports general datum transformations, making use of the
PROJ co-ordinate system translation library.
When projecting into a latlon project, east coordinates are wrapped
by the proj4 library to fit into the range -180,180. This is in most cases
appropriate, but can cause errors the input vector crosses the datum line
at 180E/W. In this case wrapping of east coordinates to -180,180 needs
to be disabled with the -w flag.
When reprojecting massive point clouds for which topology is not necessary,
the user can set the -b flag to suppress the building of topology of
the output map.
In order to preserve spatial detail, v.proj performs automated
vertex densification (as an alternative, v.split
could be used before reprojecting. Without vertex densification, depending on
the source and target CRS (Coordinate Reference System), geometries can be
substantially deformed (straight lines become curves, squares become
trapezoids, etc). The densification of linear features can help to avoid
topological errors.
Reprojection of a vector map from another project (and mapset) into the current mapset:
v.proj in=mymap project=latlong mapset=user1
- Evenden, G.I. (1990) Cartographic
projection procedures for the UNIX environment - a user's manual.
USGS Open-File Report 90-284 (OF90-284.pdf)
See also there: Interim Report and 2nd Interim Report on Release 4, Evenden 1994).
- Richards, John A. (1993), Remote Sensing Digital Image Analysis,
Springer-Verlag, Berlin, 2nd edition.
PROJ: Projection/datum support library.
Further reading
g.proj,
m.proj,
r.proj,
i.rectify,
r.stats,
v.sample,
v.split,
v.surf.idw,
v.surf.rst
Irina Kosinovsky, US ARMY CERL
M.L. Holko, USDA, SCS, NHQ-CGIS
R.L. Glenn, USDA, SCS, NHQ-CGIS
SOURCE CODE
Available at:
v.proj source code
(history)
Latest change: Tuesday Apr 09 17:19:31 2024 in commit: 1c0957876464417a8c28516d4ae9024cf4883e65
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© 2003-2024
GRASS Development Team,
GRASS GIS 8.5.0dev Reference Manual