v.proj(1grass)

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

6       v.proj   -  Re-projects  a  vector map from one location to the current
7       location.
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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]   [--overwrite]  [--help]
17       [--verbose]  [--quiet]  [--ui]
18
19   Flags:
20       -l
21           List vector maps in input mapset and exit
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23       -z
24           Assume z coordinate is ellipsoidal height and transform if possible
25           3D vector maps only
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27       -w
28           Disable wrapping to -180,180 for latlon output
29           Latlon output only, default is -180,180
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31       -b
32           Do not build vector topology
33           Recommended for massive point projection
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35       --overwrite
36           Allow output files to overwrite existing files
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38       --help
39           Print usage summary
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41       --verbose
42           Verbose module output
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44       --quiet
45           Quiet module output
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47       --ui
48           Force launching GUI dialog
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50   Parameters:
51       location=name [required]
52           Location containing input vector map
53           Location name (not location path)
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55       mapset=name
56           Mapset containing input vector map
57           Default: name of current mapset
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59       input=name
60           Name of input vector map to re-project
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62       dbase=path
63           Path to GRASS database of input location
64           Default: path to the current GRASS GIS database
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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
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71       output=name
72           Name for output vector map (default: input)
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DESCRIPTION

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

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

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

117       1      Evenden, G.I.  (1990) Cartographic projection procedures for the
118              UNIX  environment  -  a  user’s  manual.   USGS Open-File Report
119              90-284 (OF90-284.pdf) See also there:  Interim  Report  and  2nd
120              Interim Report on Release 4, Evenden 1994).
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122       2      Richards, John A. (1993), Remote Sensing Digital Image Analysis,
123              Springer-Verlag, Berlin, 2nd edition.
124
125       PROJ 4: Projection/datum support library.
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127       Further reading
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129           ·   ASPRS Grids and Datum
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131           ·   Projections Transform List (PROJ.4)
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133           ·   MapRef - The Collection of Map Projections and  Reference  Sys‐
134               tems for Europe
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136           ·   Information  and  Service System for European Coordinate Refer‐
137               ence Systems - CRS
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139           ·   Cartographical Map Projections by Carlos A. Furuti
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AUTHORS

146       Irina Kosinovsky, US ARMY CERL
147       M.L. Holko, USDA, SCS, NHQ-CGIS
148       R.L. Glenn, USDA, SCS, NHQ-CGIS
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150       Last changed: $Date: 2016-12-01 12:04:19 +0100 (Thu, 01 Dec 2016) $
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SOURCE CODE

153       Available at: v.proj source code (history)
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155       Main  index  | Vector index | Topics index | Keywords index | Graphical
156       index | Full index
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158       © 2003-2019 GRASS Development Team, GRASS GIS 7.4.4 Reference Manual
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162GRASS 7.4.4                                                          v.proj(1)