v.out.vtk - Converts a vector map to VTK ASCII
output.
v.out.vtk
v.out.vtk --help
v.out.vtk [-cn] input=name
[layer=string] [output=name]
[type=string[,string,...]]
[precision=integer] [zscale=float]
[--overwrite] [--help] [--verbose] [--quiet]
[--ui]
- -c
-
Correct the coordinates to fit the VTK-OpenGL precision
- -n
-
Export numeric attribute table fields as VTK scalar variables
- --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
- input=name
[required]
-
Name of input vector map
Or data source for direct OGR access
- layer=string
-
Layer number or name
Vector features can have category values in different layers. This number
determines which layer to use. When used with direct OGR access this is
the layer name.
Default: 1
- output=name
-
Name for output VTK file
- type=string[,string,...]
-
Input feature type
Options: point, kernel, centroid, line, boundary, area, face
Default: point,kernel,centroid,line,boundary,area,face
- precision=integer
-
Number of significant digits (floating point only)
- zscale=float
-
Scale factor for elevation
Default: 1.0
v.out.vtk converts a GRASS vector map in binary format to
the VTK ASCII output.
If the output parameter is not given, the output will be
send to stdout.
The following vector types can be exported together in one VTK
ascii file:
- point
- line
- centroid
- boundary
- area
- face
Category data (cat) for the selected vector type and layer will be written as
scalar data with name "cat_{vectorname}". If no cat exists, the
value will set to -1 as normal cat’s are always positive. If a vector
has more categories in one layer, only the first category will be exported.
3d vectors are supported by default. The created VTK data always includes x, y
and z coordinates (z = 0 if not a 3d vector map). Note that you can easily
convert your 2d vectors into 3d vectors with v.drape.
Because of the 32bit limits of OpenGL which is used by VTK, visualisation errors
may occur if the grass region contains coordinates greater than 1.000.000 and
vector coordinates with 0.01 - 0.001 meters precisison. For this reason, the
flag "-c" was added. The coordinates are transformed to smaller
coordinates (by decreasing the coordinates with the region center).
If the "-c" flag is used and the data should be visualised together
with other data exported via *.out.vtk modules, be sure the "-c"
flag was also set in these modules. But this will only work with data from the
SAME location (The reference point for the coordinates transformation is based
on the default region).
The GRASS vector data is converted into the polydata format of VTK:
- vtk Vertices -- representing points and centroids
- vtk lines -- representing lines and boundaries
- vtk polygons -- representing areas and faces
The VTK file can be visualized with VTK Toolkit,
Paraview and MayaVi.
If areas or faces are exported, the data have to be triangulated
within Paraview or MayaVi.
Spearfish example:
Export the soils with cats in layer 1:
v.out.vtk input=soils type=area layer=1 output=/tmp/soils.vtk
Export the streams with cats in layer 1:
v.out.vtk input=streams type=line layer=1 output=/tmp/streams.vtk
Write the archsite vtk output to stdout with cats in layer 1:
v.out.vtk input=archsites type=point layer=1
v.out.ascii
r.out.vtk
r3.out.vtk
Soeren Gebbert
Last changed: $Date: 2018-06-12 02:46:28 +0200 (Tue, 12 Jun
2018) $
Available at: v.out.vtk source code (history)
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