Overlays and Maps

[David Gobbi]

Hi John,

I added vtkImageBlend a few months ago.  It requires that the inputs
are of the same type, and can handle types other than unsigned char.
It passes the data instead of copying if there is only one input
(wouldn't want to waste memory, would we!)

The best thing to do is probably to send the float scalars through
vtkImageMapToColors(), then into vtkImageBlend() along with the
terrain data.  If you need to resample the float scalars to the
same extent & data spacing as terrain bitmap you can use 
vtkImageReslice and set the OutputSpacing(), OutputExtent(),
and OutputOrigin() to be the same as the terrain bitmap.

 - David

--
  David Gobbi, MSc                    dgobbi at irus.rri.on.ca
  Advanced Imaging Research Group
  Robarts Research Institute, University of Western Ontario

On Wed, 17 May 2000, John Biddiscombe wrote:

> If I have a map (textured onto terrain) and some data representing Field
> Strength of a radio signal, I'm looking for good blending algorithms that
> combine the two in a pleasing and informative way. I'm guessing that this
> sort of thing has been done many times by readers so any pointers would be
> welcome.
> 
> (Map will be RGB, data just float scalars - conversion of both to char
> likely to be needed)
> 
> Any existing imagefilters designed for this kind of thing (other than
> ImageCast and ImageMathematics of course)
> 
> thanks
> 
> John B
> 
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