1v.proj(1) GRASS GIS User's Manual v.proj(1)
2
6 v.proj - Re-projects a vector map from one location to the current lo‐
7 cation.
8
10 vector, projection, transformation, import
11
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 Flags:
20 -l
21 List vector maps in input mapset and exit
22 -z
24 Assume z coordinate is ellipsoidal height and transform if possible
25 3D vector maps only
26 -w
28 Disable wrapping to -180,180 for latlon output
29 Latlon output only, default is -180,180
30 -b
32 Do not build vector topology
33 Recommended for massive point projection
34 --overwrite
36 Allow output files to overwrite existing files
37 --help
39 Print usage summary
40 --verbose
42 Verbose module output
43 --quiet
45 Quiet module output
46 --ui
48 Force launching GUI dialog
49 Parameters:
51 location=name [required]
52 Location containing input vector map
53 Location name (not location path)
54 mapset=name
56 Mapset containing input vector map
57 Default: name of current mapset
58 input=name
60 Name of input vector map to re-project
61 dbase=path
63 Path to GRASS database of input location
64 Default: path to the current GRASS GIS database
65 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 output=name
72 Name for output vector map (default: input)
73 pipeline=string
75 PROJ pipeline for coordinate transformation
76
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 For an introduction to map projections (with PROJ),see the manual page
86 of r.proj.
87
89 If output is not specified it is set to be the same as input map name.
90 If mapset is not specified, its name is assumed to be the same as the
91 current mapset’s name.
92 If dbase is not specified it is assumed to be the current database. The
93 user only has to specify dbase if the source location is stored in an‐
94 other separate GRASS database.
95 If smax is set to 0 the automated vertex densification is disabled (not
96 recommended).
97 v.proj supports general datum transformations, making use of the PROJ
99 co-ordinate system translation library.
100 When projecting into a latlon location, east coordinates are wrapped by
102 the proj4 library to fit into the range -180,180. This is in most cases
103 appropriate, but can cause errors the input vector crosses the datum
104 line at 180E/W. In this case wrapping of east coordinates to -180,180
105 needs to be disabled with the -w flag.
106 When reprojecting massive point clouds for which topology is not neces‐
108 sary, the user can set the -b flag to suppress the building of topology
109 of the output map.
110 In order to preserve spatial detail, v.proj performs automated vertex
112 densification (as an alternative, v.split could be used before repro‐
113 jecting. Without vertex densification, depending on the source and tar‐
114 get CRS (Coordinate Reference System), geometries can be substantially
115 deformed (straight lines become curves, squares become trapezoids,
116 etc). The densification of linear features can help to avoid topologi‐
117 cal errors.
118
120 Reprojection of a vector map from another location and mapset into the
121 current mapset:
122 v.proj in=mymap location=latlong mapset=user1
123
125 1 Evenden, G.I. (1990) Cartographic projection procedures for the
126 UNIX environment - a user’s manual. USGS Open-File Report
127 90-284 (OF90-284.pdf) See also there: Interim Report and 2nd In‐
128 terim Report on Release 4, Evenden 1994).
129 2 Richards, John A. (1993), Remote Sensing Digital Image Analysis,
131 Springer-Verlag, Berlin, 2nd edition.
132 PROJ: Projection/datum support library.
134 Further reading
136 • ASPRS Grids and Datum
138 • Projections Transform List (PROJ)
140 • Coordinate operations by PROJ (projections, conversions, trans‐
142 formations, pipeline operator)
143 • MapRef - The Collection of Map Projections and Reference Sys‐
145 tems for Europe
146 • Information and Service System for European Coordinate Refer‐
148 ence Systems - CRS
149
151 g.proj, m.proj, r.proj, i.rectify, r.stats, v.sample, v.split,
152 v.surf.idw, v.surf.rst
153
155 Irina Kosinovsky, US ARMY CERL
156 M.L. Holko, USDA, SCS, NHQ-CGIS
157 R.L. Glenn, USDA, SCS, NHQ-CGIS
158
160 Available at: v.proj source code (history)
161 Accessed: Mon Jun 20 16:47:04 2022
163 Main index | Vector index | Topics index | Keywords index | Graphical
165 index | Full index
166 © 2003-2022 GRASS Development Team, GRASS GIS 8.2.0 Reference Manual
168GRASS 8.2.0 v.proj(1)