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

NAME
       r.out.vtk  - Converts raster maps into the VTK-ASCII format.

KEYWORDS
       raster, export, output, VTK

SYNOPSIS
       r.out.vtk
       r.out.vtk --help
       r.out.vtk  [-pstvoc]  [input=name[,name,...]]   [output=name]   [eleva-
       tion=name]   [null=float]    [z=float]	 [rgbmaps=string[,string,...]]
       [vectormaps=string[,string,...]]	  [zscale=float]   [precision=integer]
       [--overwrite]  [--help]	[--verbose]  [--quiet]	[--ui]

   Flags:
       -p
	   Create VTK point data instead of VTK	cell data (if no elevation map
	   is given)

       -s
	   Use structured grid for elevation (not recommended)

       -t
	   Use polydata-trianglestrips for elevation grid creation

       -v
	   Use	polydata-vertices  for	elevation  grid	 creation (to use with
	   vtkDelauny2D)

       -o
	   Scale factor	affects	the origin (if no elevation map	is given)

       -c
	   Correct the coordinates to match the	VTK-OpenGL precision

       --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[,name,...]
	   Raster map(s) to be converted to VTK-ASCII data format

       output=name
	   Name	for VTK-ASCII output file

       elevation=name
	   Name	of input elevation raster map

       null=float
	   Value to represent no data cell
	   Default: -99999.99

       z=float
	   Constant elevation (if no elevation map is specified)
	   Default: 0.0

       rgbmaps=string[,string,...]
	   Three (r,g,b) raster	 maps  to  create  RGB	values	[redmap,green-
	   map,bluemap]

       vectormaps=string[,string,...]
	   Three (x,y,z) raster	maps to	create vector values [xmap,ymap,zmap]

       zscale=float
	   Scale factor	for elevation
	   Default: 1.0

       precision=integer
	   Number of significant digits	(floating point	only)
	   Options: 0-20
	   Default: 12

DESCRIPTION
       Outputs	raster	maps in	VTK-ASCII format. Map's	are valid raster map's
       in the current mapset.  output is the name of an	VTK-ASCII  file	 which
       will  be	 written  in  the current working directory.  If output	is not
       specified then stdout is	used.  The module is sensitive to region  set-
       tings (set with g.region).

       Elevation,  scaling, point/celldata, vector and RGB Data	are supported.
       If the map is in	LL projection, the elevation values will automatically
       scaled  to  degrees.  It	is supposed that the elevation values are pro-
       vided in	meters.	 If the	elevation values are in	a different unit  than
       meters, use the scale parameter to convert the units.

       If no elevation map is given, the user can set the height of the	map by
       one value.  Point or cell data are available. Also scaling is supported
       for  this elevation value.  The elevation value must be provided	in me-
       ters.

       The RGB input requires three raster maps: red, green, blue  -  in  this
       order.  The maps	must have values between 0 and 255, otherwise you will
       get lots	of warnings and	the values are set to 0.  More	than  one  RGB
       dataset (3 maps)	is not supported.

       The  vector  input  requires three raster maps: x, y, z -- defining the
       vector coordinates  - in	this order.  More than one vector  dataset  (3
       maps) is	not supported.

NOTES
       This filter generates:

	   o   structured  points  with	celldata or pointdata if no elevation-
	       file is given

	   o   structured grid (not recommendet) with pointdata	if  an	eleva-
	       tionfile	is given

	   o   polydataset  with  pointdata  if	an elevationfile is given (de-
	       fault)
       and puts	this in	a simple VTK-ASCII file. Nor XML or binary output  are
       supported.  It  is  possible  to	 choose	more then one raster map to be
       written to the VTK-ASCII	file. Each cell-/pointdata is named  like  the
       raster  map  it	represents.   You can visualize	this file with the VTK
       Toolkit,	Paraview and MayaVi which are based on VTK.   If  you  have  a
       raster map with partly no data, use the threshold filter	in paraview to
       visualize the valid data. Just filter all data which is	greater/lesser
       than the	chosen null value in the VTK-ASCII file.
       If elevation map	is chosen, a polygonal grid is created with quads, but
       the user	can choose also	triangle strips	or vertices.   These  datafor-
       mats a documented at VTK	Toolkit.

       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 center point of the	default	region).

   Difference between point- and celldata
       r.out.vtk can export raster cells with different	representations.

	   o   pointdata  -- the cells/values are represented by the center of
	       the cell.  Instead of cells, points are created.	Each point can
	       hold  different	values,	 but  the  user	can only visualize one
	       value at	a time.	These points can  be  connected	 in  different
	       ways.

	   o   celldata	-- is only provided if no elevation map	is given.  The
	       cells are created with the same hight and width	as  in	GRASS.
	       Each  cell can hold different values, but the user can only vi-
	       sualize one value at a time.

EXAMPLE
   Simple Spearfish example
       # set region
       g.region	n=4926970 s=4914857 w=591583 e=607793 res=50 -p
       # export	the data
       r.out.vtk input=elevation.10m,slope,aspect elevation=elevation.10m output=/tmp/out.vtk
       # visualize in Paraview or other	VTK viewer:
       paraview	--data=/tmp/out.vtk

   Spearfish example with RGB data
       #set the	region
       g.region	n=4926990 s=4914840 w=591570 e=607800 res=30 -p
       # using r.in.wms	to create RGB data to get a satellite coverage
       r.in.wms	layers=global_mosaic mapserver=http://wms.jpl.nasa.gov/wms.cgi \
		output=wms_global_mosaic
       # export	the data to VTK
       r.out.vtk rgbmaps=wms_global_mosaic.red,wms_global_mosaic.green,wms_global_mosaic.blue \
		 elevation=elevation.10m output=/tmp/out.vtk
       # visualize in Paraview or other	VTK viewer:
       paraview	--data=/tmp/out.vtk
       Paraview	RGB visualization notes
       To achieve proper RGB overlay:

	   o   In Paraview, click "Apply"

	   o   Select the "Display" tab	and choose "Color by" to  switch  from
	       input scalars to	rgb scalars

	   o   Disable	the  "Map  Scalars" check button in the	display	tab to
	       avoid the use of	a lookup table

SEE ALSO
	r3.out.vtk, r.out.ascii, g.region
       GRASS and Paraview Wiki page

AUTHOR
       Soeren Gebbert

SOURCE CODE
       Available at: r.out.vtk source code (history)

       Main index | Raster 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							  r.out.vtk(1)

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

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