Re: absolute or relative color tables? - more

  • Subject: Re: absolute or relative color tables? - more
  • From: Stuart Wier <wier@xxxxxxxxxxxxxxxx>
  • Date: Wed, 02 Aug 2000 08:37:07 -0600
> > How do I make a color table or ColorControl so that there
> > is a connection between a particular color and a particular data
> > value or a range of data values?
> >
> > So far as I know a color table in VisAD spans whatever values are displayed.
> > Two displays of the same parameter (but different max and mins)
> > have differing colors for the same parameter value; very confusing.
> >
> This mapping is determined by the low and high values passed
> to ScalarMap.setRange(), and by the 'float[][] table' array
> passed to BaseColorControl.setTable().  The table values
> (length = table[0].length) are distributed evenly over the
> (low, high) range.  If an application does not call setRange(),
> then the range is determined by the range of values in
> displayed data objects.

So there is no way to say "make data values of 0.0 always blue 
wherever they occur"?

A more complex case is where you don't want colors evenly distributed
over the low, high range.  For example, having a special and
rapidly changing list of distinctive colors associated with a narrow
range of data values of primary interest, imbedded in a larger (low, high) range
of lesser interest?  For example in medical imagery
where you want to highlite a particular signal value.

Stu Wier    

Unidata Program Center
P.O. Box 3000
Boulder, CO 80307

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