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

6       v.extrude   -  Extrudes flat vector features to 3D vector features with
7       defined height.
8       Optionally the height can be derived from sampling of elevation  raster
9       map.
10

KEYWORDS

12       vector, geometry, sampling, 3D
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SYNOPSIS

15       v.extrude
16       v.extrude --help
17       v.extrude     [-t]     input=name      [layer=string]      [cats=range]
18       [where=sql_query]         [type=string[,string,...]]        output=name
19       [zshift=float]      [height=float]     [height_column=name]     [eleva‐
20       tion=name]     [method=string]     [scale=float]     [null_value=float]
21       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]
22
23   Flags:
24       -t
25           Trace elevation
26
27       --overwrite
28           Allow output files to overwrite existing files
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30       --help
31           Print usage summary
32
33       --verbose
34           Verbose module output
35
36       --quiet
37           Quiet module output
38
39       --ui
40           Force launching GUI dialog
41
42   Parameters:
43       input=name [required]
44           Name of input vector map
45           Or data source for direct OGR access
46
47       layer=string
48           Layer number or name (’-1’ for all layers)
49           A  single  vector map can be connected to multiple database tables.
50           This number determines which table to use. When  used  with  direct
51           OGR access this is the layer name.
52           Default: -1
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54       cats=range
55           Category values
56           Example: 1,3,7-9,13
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58       where=sql_query
59           WHERE conditions of SQL statement without ’where’ keyword
60           Example: income < 1000 and population >= 10000
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62       type=string[,string,...]
63           Input feature type
64           Options: point, line, area
65           Default: point,line,area
66
67       output=name [required]
68           Name for output vector map
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70       zshift=float
71           Shifting value for z coordinates
72           Default: 0
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74       height=float
75           Fixed height for 3D vector features
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77       height_column=name
78           Name of attribute column with feature height
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80       elevation=name
81           Elevation raster map for height extraction
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83       method=string
84           Sampling interpolation method
85           Options: nearest, bilinear, bicubic
86           Default: nearest
87           nearest: Nearest-neighbor interpolation
88           bilinear: Bilinear interpolation
89           bicubic: Bicubic interpolation
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91       scale=float
92           Scale factor sampled raster values
93           Default: 1.0
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95       null_value=float
96           Height for sampled raster NULL values
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DESCRIPTION

99       v.extrude  creates  faces, kernels or 3D lines based on input 2D vector
100       features. Points are converted to 3D vertical lines, lines to faces and
101       areas to volumes (composition of closed set of faces and kernel).
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103       If  elevation parameter is used then 3D vector features follow the ele‐
104       vation model by using individual elevation  values  for  the  vertices.
105       Height  for  vertices  is  interpolated from elevation raster map using
106       given interpolation method.
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NOTES

109       v.extrude extrudes vector features which means  that  points  are  con‐
110       verted  to  vertical lines. Lines and area boundaries are extruded to a
111       set of faces, each segment defines one face. Area centroids are written
112       as  kernels. Area as a composition of boundaries and centroid is stored
113       as a closed set of faces and kernel which define a volume.
114
115       For conversion of 2D points or lines to  3D  can  be  used  v.to.3d  or
116       v.drape.  In opposite to v.extrude, these modules do not extrude vector
117       features, they defines z-coordinate for the features from given parame‐
118       ters  or by sampling elevation raster map values. It means that no fea‐
119       ture type conversion is applied, points remain still points in the out‐
120       put vector map. Same applies for the lines.
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122       v.extrude  modifies  only  features geometry. Feature categories remain
123       untouched and attribute data is copied from input  vector  map  to  the
124       output.
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126       By  default,  all  features  (including features without category) from
127       input vector map are processed (layer=-1).  Feature  selection  can  be
128       applied by layer, cats or where parameter.
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EXAMPLES

131   3D houses with fixed height
132       v.extrude input=houses output=houses3D height=5 type=area
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134   3D houses with individual height
135       v.extrude input=houses output=houses3D elevation=dem height_column=height type=area
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137   Convert 2D points to 3D vertical lines with fixed height
138       v.extrude input=geodetic_pts output=points3D height=200 type=point
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SEE ALSO

141        v.transform, v.drape, v.to.3d
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143        wxGUI 3D viewer
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AUTHORS

146       Jachym Cepicky,
147       Updated  for GRASS 7 by Martin Landa, FBK-irst, Italy and Czech Techni‐
148       cal University in Prague, Czech Republic
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SOURCE CODE

151       Available at: v.extrude source code (history)
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153       Main index | Vector index | Topics index | Keywords index  |  Graphical
154       index | Full index
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156       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual
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160GRASS 7.8.2                                                       v.extrude(1)