.TH v.out.vtk 1grass "" "GRASS 6.4.4" "Grass User's Manual"
.SH NAME
\fI\fBv.out.vtk\fR\fR  - Converts a GRASS binary vector map to VTK ASCII output.
.SH KEYWORDS
vector, export
.SH SYNOPSIS
\fBv.out.vtk\fR
.br
\fBv.out.vtk help\fR
.br
\fBv.out.vtk\fR [\-\fBcn\fR] \fBinput\fR=\fIname\fR  [\fBoutput\fR=\fIstring\fR]   [\fBtype\fR=\fIstring\fR[,\fIstring\fR,...]]   [\fBdp\fR=\fIinteger\fR]   [\fBscale\fR=\fIfloat\fR]   [\fBlayer\fR=\fIinteger\fR]   [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR] 
.SS Flags:
.IP "\fB\-c\fR" 4m
.br
Correct the coordinates to fit the VTK-OpenGL precision
.IP "\fB\-n\fR" 4m
.br
Export numeric attribute table fields as VTK scalar variables
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.PP
.SS Parameters:
.IP "\fBinput\fR=\fIname\fR" 4m
.br
Name of input vector map
.IP "\fBoutput\fR=\fIstring\fR" 4m
.br
Path to resulting VTK file
.IP "\fBtype\fR=\fIstring[,\fIstring\fR,...]\fR" 4m
.br
Feature type
.br
Options: \fIpoint,kernel,centroid,line,boundary,area,face\fR
.br
Default: \fIpoint,kernel,centroid,line,boundary,area,face\fR
.IP "\fBdp\fR=\fIinteger\fR" 4m
.br
Number of significant digits (floating point only)
.IP "\fBscale\fR=\fIfloat\fR" 4m
.br
Scale factor for elevation
.br
Default: \fI1.0\fR
.IP "\fBlayer\fR=\fIinteger\fR" 4m
.br
Layer number
.br
Default: \fI1\fR
.PP
.SH DESCRIPTION
\fIv.out.vtk\fR 
converts a GRASS vector map in binary format to the VTK ASCII 
output. 
.PP
If the \fBoutput\fR parameter is not given, the output will be send to stdout.
.SH NOTES
The following vector types can be exported together in one VTK ascii file:
.RE
point
line
centroid
boundary
area
face
.RE
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.
.br
.br
All numeric attribute fields of a given layer of the input map can be exported as scalar VTK
variables using the "-n" flag.
.br
.br
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.
.br
.br
Because of the 32bit limits of OpenGL which is used by VTK, visualisation errors may occure 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).
.br
.br
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).
.br
.br
The GRASS vector data is converted into the polydata format of VTK: 
.RE
\fIvtk Vertices\fR -- representing points and centroids 
\fIvtk lines\fR -- representing lines and boundaries  
\fIvtk polygons\fR -- representing areas and faces 
.RE
.PP
The VTK file can be visualized with
\fIVTK Toolkit\fR,
\fIParaview\fR and
\fIMayaVi\fR.
.SS Attention
If areas or faces are exported, the data have to be triangulated within Paraview or
MayaVi.
.SH EXAMPLE
Spearfish example:
.PP
Export the soils with cats in layer 1:
\fC
.DS
.br
v.out.vtk input=soils type=area layer=1 output=/tmp/soils.vtk
.br
.DE
\fR
Export the streams with cats in layer 1:
\fC
.DS
.br
v.out.vtk input=streams type=line layer=1 output=/tmp/streams.vtk
.br
.DE
\fR
Write the archsite vtk output to stdout with cats in layer 1:
\fC
.DS
.br
v.out.vtk input=archsites type=point layer=1
.br
.DE
\fR
.SH SEE ALSO
\fI
v.out.ascii
.br
r.out.vtk
.br
r3.out.vtk
.br
\fR
.SH AUTHOR
Soeren Gebbert
.PP
Full index
.PP
© 2003-2014 GRASS Development Team