[vtkusers] vtkLookUpTable not well defined for NaNs

[Sarah Macumber]

Hello,

 

I was hoping someone could help with mapping scalar data containing NaNs
through a vtkLookUpTable where one wants the NaNs to be a certain color.
Internally vtkLookUpTable uses the range to determine the index of the
color used for a specific scalar value:

 

                index = (value-min)/(max-min)*(N-1)

 

which means that NaNs do not have well defined index.  Currently, NaN's
default to an index of 0.  Changing the 0th color value conflicts with
the min scalar value being displayed which also has an index of 0.

 

Is there any way to set the color of a NaN using a vtkLookUpTable
without it conflicting with the viewable data?

 

Thanks,

Sarah

 

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