[vtkusers] Problem getting correct results with vtkProjectedTerrainPath

Elvis Dowson elvis.dowson at mac.com
Mon Nov 10 13:21:57 EST 2008

Hi Amy,
                  Could you please help me out by giving me a code  
fragment on how to achieve this? I have created an outline below.

I've created a vtkImageData and set it's dimensions by reading the max  
extent of the original DEM file. I hope that is correct. Now  
vtkProjectedPath::SetSource(vtkImageData* ) expects a vtkImageData*,  
and I don't know how to pass the vtkImageData object called  
elevationData to this method. I have highlighted it in red below.

I have put the wrap scalar code fragment below. Could you please help  
me with a code fragment to extract the vtkImageData from the wrap  
scalar output?

# Create a reader to read the unstructured grid data.
vtkDataSetReader reader
     reader SetFileName "SampleDEM.vtk"

# Get the physical xy extent of dataset
scan [[reader GetOutput] GetWholeExtent] "%d %d %d %d %d %d" XminR  
XmaxR YminR YmaxR ZminR ZmaxR


# Now warp the surface based on the scalar elevation values
# This creates the 3D mesh model of the terrain.
vtkWarpScalar surface
   surface SetInput [geom GetOutput]
   surface SetScaleFactor 0.1; # $scale variable controls vertical  


# Use a probe filter to obtain elevation data from the reconstructed  
vtkImageData elevationData
   elevationData SetDimensions $XmaxR $YmaxR $ZmaxR


vtkProjectedTerrainPath projectedPaths
   projectedPaths SetInput terrainPaths
   projectedPaths SetSource [elevationData]
   projectedPaths SetHeightOffset 25
   projectedPaths SetHeightTolerance 5
   projectedPaths SetProjectionModeToNonOccluded
   projectedPaths SetProjectionModeToHug

Best regards,

Elvis Dowson

On Nov 10, 2008, at 6:31 PM, Amy Squillacote wrote:

> Hi Elvis,
> You could try using a vtkProbeFilter: http://www.vtk.org/doc/nightly/html/classvtkProbeFilter.html 
> . Create an empty vtkImageData (sized and positioned to encompass  
> the output of your vtkWarpScalar filter), and pass it as the  
> "source" (2nd input) to vtkProbeFilter.
> - Amy
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