1v.proj(1)                     Grass User's Manual                    v.proj(1)
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4

NAME

6       v.proj   -  Re-projects  a  vector map from one location to the current
7       location.
8

KEYWORDS

10       vector, projection, transformation, import
11

SYNOPSIS

13       v.proj
14       v.proj --help
15       v.proj    [-lzwb]    location=name     [mapset=name]       [input=name]
16       [dbase=path]      [smax=float]      [output=name]     [pipeline=string]
17       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]
18
19   Flags:
20       -l
21           List vector maps in input mapset and exit
22
23       -z
24           Assume z coordinate is ellipsoidal height and transform if possible
25           3D vector maps only
26
27       -w
28           Disable wrapping to -180,180 for latlon output
29           Latlon output only, default is -180,180
30
31       -b
32           Do not build vector topology
33           Recommended for massive point projection
34
35       --overwrite
36           Allow output files to overwrite existing files
37
38       --help
39           Print usage summary
40
41       --verbose
42           Verbose module output
43
44       --quiet
45           Quiet module output
46
47       --ui
48           Force launching GUI dialog
49
50   Parameters:
51       location=name [required]
52           Location containing input vector map
53           Location name (not location path)
54
55       mapset=name
56           Mapset containing input vector map
57           Default: name of current mapset
58
59       input=name
60           Name of input vector map to re-project
61
62       dbase=path
63           Path to GRASS database of input location
64           Default: path to the current GRASS GIS database
65
66       smax=float
67           Maximum segment length in meters in output vector map
68           Increases accuracy of reprojected shapes, disable with smax=0
69           Default: 10000
70
71       output=name
72           Name for output vector map (default: input)
73
74       pipeline=string
75           PROJ pipeline for coordinate transformation
76

DESCRIPTION

78       v.proj allows a user to convert a vector map in a specified mapset of a
79       specified  location  (different  from current) with projection of input
80       location to the vector map in a current mapset of current location with
81       projection  of current location (both projections are defined by corre‐
82       sponding PROJ_INFO files). The projection information is taken from the
83       current PROJ_INFO files, as set and viewed with g.proj.
84

NOTES

86       If output is not specified it is set to be the same as input map name.
87       If  mapset  is not specified, its name is assumed to be the same as the
88       current mapset’s name.
89       If dbase is not specified it is assumed to be the current database. The
90       user  only  has  to  specify  dbase if the source location is stored in
91       another separate GRASS database.
92       If smax is set to 0 the automated vertex densification is disabled (not
93       recommended).
94
95       v.proj supports general datum transformations, making use of the PROJ.4
96       co-ordinate system translation library.
97
98       When projecting into a latlon location, east coordinates are wrapped by
99       the proj4 library to fit into the range -180,180. This is in most cases
100       appropriate, but can cause errors the input vector  crosses  the  datum
101       line  at  180E/W. In this case wrapping of east coordinates to -180,180
102       needs to be disabled with the -w flag.
103
104       When reprojecting massive point clouds for which topology is not neces‐
105       sary, the user can set the -b flag to suppress the building of topology
106       of the output map.
107
108       In order to preserve spatial detail, v.proj performs  automated  vertex
109       densification  (as  an alternative, v.split could be used before repro‐
110       jecting. Without vertex densification, depending on the source and tar‐
111       get  CRS (Coordinate Reference System), geometries can be substantially
112       deformed (straight lines  become  curves,  squares  become  trapezoids,
113       etc).  The densification of linear features can help to avoid topologi‐
114       cal errors.
115

EXAMPLES

117       v.proj in=mymap location=latlong mapset=user1
118

REFERENCES

120       1      Evenden, G.I.  (1990) Cartographic projection procedures for the
121              UNIX  environment  -  a  user’s  manual.   USGS Open-File Report
122              90-284 (OF90-284.pdf) See also there:  Interim  Report  and  2nd
123              Interim Report on Release 4, Evenden 1994).
124
125       2      Richards, John A. (1993), Remote Sensing Digital Image Analysis,
126              Springer-Verlag, Berlin, 2nd edition.
127
128       PROJ 4: Projection/datum support library.
129
130       Further reading
131
132           ·   ASPRS Grids and Datum
133
134           ·   Projections Transform List (PROJ.4)
135
136           ·   MapRef - The Collection of Map Projections and  Reference  Sys‐
137               tems for Europe
138
139           ·   Information  and  Service System for European Coordinate Refer‐
140               ence Systems - CRS
141
142           ·   Cartographical Map Projections by Carlos A. Furuti
143

SEE ALSO

145         g.proj,  m.proj,  r.proj,  i.rectify,  r.stats,  v.sample,   v.split,
146       v.surf.idw, v.surf.rst
147

AUTHORS

149       Irina Kosinovsky, US ARMY CERL
150       M.L. Holko, USDA, SCS, NHQ-CGIS
151       R.L. Glenn, USDA, SCS, NHQ-CGIS
152

SOURCE CODE

154       Available at: v.proj source code (history)
155
156       Main  index  | Vector index | Topics index | Keywords index | Graphical
157       index | Full index
158
159       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual
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163GRASS 7.8.2                                                          v.proj(1)
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