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NAME

       r3.out.vtk  - Converts 3D raster maps into the VTK-ASCII format.

KEYWORDS

       raster3d, export, output, voxel, VTK

SYNOPSIS

       r3.out.vtk
       r3.out.vtk --help
       r3.out.vtk    [-psmocl]     [input=name[,name,...]]      [output=name]      [null=float]     [top=string]
       [bottom=string]       [rgbmaps=name[,name,...]]        [vectormaps=name[,name,...]]        [zscale=float]
       [precision=integer]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -p
           Create VTK pointdata instead of VTK celldata (celldata is default)

       -s
           Create 3D elevation output with a top and a bottom surface, both raster maps are required.

       -m
           Use 3D raster mask (if exists) with input maps

       -o
           Scale factor affects the origin

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

       -l
           Do not convert the top-bottom resolution in case of lat long projection to meters

       --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,...]
           3D raster map(s) to be converted to VTK-ASCII data format

       output=name
           Name for VTK-ASCII output file

       null=float
           Float value to represent no data cell/points
           Default: -99999.99

       top=string
           Top surface 2D raster map

       bottom=string
           Bottom surface 2D raster map

       rgbmaps=name[,name,...]
           Three (R,G,B) 3D raster maps to create RGB values [redmap,greenmap,bluemap]

       vectormaps=name[,name,...]
           Three (x,y,z) 3D 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

       The module r3.out.vtk outputs 3D raster maps into VTK-ASCII format.  Maps are valid 3D raster maps in the
       current mapset search path. The output parameter is the name of a VTK-ASCII file which will be written in
       the  current  working  directory.  If  output is not specified then standard output (stdout) is used. The
       module is sensitive to region settings (set with g.region).

NOTES

       This module generates structured points with celldata (default) or pointdata. If top and bottom  surfaces
       are  requested an unstructured grid with celldata or a structured grid with pointdata is generated.  This
       data is put in a simple VTK-ASCII file. Neither XML nor binary output are supported. It  is  possible  to
       choose  more then one 3D raster map to be written in the VTK-ASCII file. Each celldata is named as the 3D
       raster map it represents. The user can visualize this file with the  VTK  Toolkit,  ParaView  and  MayaVi
       which are based on VTK. In case of 3D raster map with partially no data, the threshold filter in ParaView
       can be used to visualize the valid data. Just filter all data which is  greater/lesser  than  the  chosen
       null value in the VTK-ASCII file.

       The  top  and  bottom region values are expected in meters.  If a Latitude-Longitude (LL) coordinates are
       used, the elevation value for each voxel will be converted into degrees.

       The input, rgbmaps and vectormaps parameters are optional, so only the geometry can be exported.

       If the user defines top and bottom and the 2D and 3D region values differ,  the  2D  resolution  will  be
       adjusted  to  the  3D  resolution. The elevation maps are expected in meters. If Lat/Long coordinates are
       used, the elevation will automatically converted into degree.  If the surface and bottom maps  are  in  a
       different unit than meters, use the scale parameter to convert them into meters.

       The  RGB voxel data can be created from 2D raster maps (Landsat TM images) with r.to.rast3. The values of
       the RGB maps must be within 0 and 255. If not, the values are automatically set to 0 and warnings will be
       printed to stderr.

       The  vector  data  is created from three 3D raster maps. Each map represents a vector component.  So x, y
       and z components are required in this order. This data can be visualized  with  Glyph3d  or  StreamTracer
       filters within Paraview.

       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 center point of the
       default region).

   Difference between point- and celldata
       r3.out.vtk can export 3D raster maps with different representations.

           •   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.

           •   celldata The cells are created with the same hight, width and depth as in GRASS.  Each  cell  can
               hold different values, but the user can only visualize one value at a time.

EXAMPLE

   Simple Spearfish example
       g.region -d
       g.region res=150 res3=150 t=80 b=0 tbres=10
       r.mapcalc "bottom = 1800. - elevation.10m"
       # synthetic data, could be geological structures:
       r3.mapcalc "map3d = row()+col()+depth()"
       #export of volume to VTK:
       r3.out.vtk -s input=map3d top=elevation.10m bottom=bottom 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 -d
       g.region n=4926970 s=4914857 w=591583 e=607793 res=50 res3=50 t=80 b=0 tbres=10
       #create a bottom surface
       r.mapcalc "bottom = 1800. - elevation.10m"
       # synthetic data, could be geological structures:
       r3.mapcalc "map3d = row()+col()+depth()"
       #get some satellite images with r.in.onearth
       r.in.onearth -l output=Sat tmband=Red
       r.in.onearth -l output=Sat tmband=IR1
       r.in.onearth -l output=Sat tmband=IR2
       #Convert the 2D maps to 3D raster maps with r.to.rast3
       r.to.rast3 input=SatLandsatTM_Red output=SatLandsatTM_Red
       r.to.rast3 input=SatLandsatTM_IR1 output=SatLandsatTM_IR1
       r.to.rast3 input=SatLandsatTM_IR2 output=SatLandsatTM_IR2
       #export of volume to VTK:
       r3.out.vtk -s rgbmaps=SatLandsatTM_IR1,SatLandsatTM_IR2,SatLandsatTM_Red
       input=map3d top=elevation.10m bottom=bottom output=/tmp/out.vtk
       # visualize in paraview or other VTK viewer:
       paraview --data=/tmp/out.vtk

   Spearfish example with vector data
       # set the region
       g.region -d
       g.region n=4926970 s=4914857 w=591583 e=607793 res=50 res3=50 t=80 b=0 tbres=10
       # create a bottom surface
       r.mapcalc "bottom = 1800. - elevation.10m"
       # synthetic data, could be geological structures:
       r3.mapcalc "map3d = row()+col()+depth()"
       # synthetic vector data, could be groundwater stream vectors
       r3.mapcalc "x_part = sin(row())"
       r3.mapcalc "y_part = cos(col())"
       r3.mapcalc "z_part = sin(depth())"
       # export the stuff data to VTK:
       r3.out.vtk -s vectormaps=x_part,y_part,z_part input=map3d top=elevation.10m
       bottom=bottom output=/tmp/out.vtk
       # visualize in paraview or other VTK viewer:
       paraview --data=/tmp/out.vtk
       # Now use the Glyph and Stream-Trace Filter to get nice vectors and streamlines

   Slovakia3d example
       #reduce resolution:
       g.region -dp3 res=1000 res3=1000
       r.mapcalc "bottom = 100"
       #export of volume to VTK:
       r3.out.vtk -s in=precip3d.500z50 top=dem500 bottom=bottom \
          output=/path/to/slovakia3d.vtk
       # visualize in paraview or other VTK viewer:
       paraview --data=/path/to/slovakia3d.vtk
       # set Display style to ’surface#
       # set Actor Control z to 10

SEE ALSO

        r.out.vtk, r3.out.ascii, g.region

AUTHOR

       Sören Gebbert

SOURCE CODE

       Available at: r3.out.vtk source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual