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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]     [elevation=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,greenmap,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 settings (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
       provided 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 meters.

       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:

           •   structured points with celldata or pointdata if no elevationfile is given

           •   structured grid (not recommendet) with pointdata if an elevationfile is given

           •   polydataset with pointdata if an elevationfile is given (default)
       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 dataformats 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  transformation  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.

           •   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.

           •   celldata  --  is only provided if no elevation map is given.  The cells are created with the same
               height and width as in GRASS. Each cell  can  hold  different  values,  but  the  user  can  only
               visualize 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:

           •   In Paraview, click "Apply"

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

           •   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)

       Accessed: Monday Apr 01 03:07:44 2024

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

GRASS 8.3.2                                                                                    r.out.vtk(1grass)