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v.out.vtk(1)		    GRASS GIS User's Manual		  v.out.vtk(1)

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=nameA [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 ac-
	   cess	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

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  std-
       out.

NOTES
       The  following  vector  types can be exported together in one VTK ascii
       file:

	   o   point

	   o   line

	   o   centroid

	   o   boundary

	   o   area

	   o   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  in-
       cludes  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, visualisa-
       tion errors may occur if	the grass region contains coordinates  greater
       than 1.000.000 and vector coordinates with 0.01 - 0.001 meters precisi-
       son. 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 transforma-
       tion is based on	the default region).
       The GRASS vector	data is	converted into the polydata format of VTK:

	   o   vtk Vertices -- representing points and centroids

	   o   vtk lines -- representing lines and boundaries

	   o   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)

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

       A(C) 2003-2020 GRASS Development	Team, GRASS GIS	7.8.5 Reference	Manual

GRASS 7.8.5							  v.out.vtk(1)

NAME | KEYWORDS | SYNOPSIS | DESCRIPTION | NOTES | EXAMPLE | SEE ALSO | AUTHOR | SOURCE CODE

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