NAME

       v.out.vtk  - Converts a vector map to VTK ASCII output.

KEYWORDS

       vector, export, output, VTK

SYNOPSIS

       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]

   Flags:
       -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

   Parameters:
       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

       zscale=float
           Scale factor for elevation
           Default: 1.0

DESCRIPTION

       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.

NOTES

       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.

   Attention
       If areas or faces are exported, the data have to be triangulated within Paraview or MayaVi.

EXAMPLE

       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

SEE ALSO

        v.out.ascii, r.out.vtk, r3.out.vtk

AUTHOR

       Soeren Gebbert

SOURCE CODE

       Available at: v.out.vtk source code (history)

       Accessed: Monday Apr 01 03:08:49 2024

       Main index | Vector index | Topics index | Keywords index | Graphical index | Full index

       © 2003-2024 GRASS Development Team, GRASS GIS 8.3.2 Reference Manual

GRASS 8.3.2                                                                                    v.out.vtk(1grass)