| Colorbar Thinking in the Shower [message #77572] |
Tue, 13 September 2011 09:28 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Folks,
I believe the best place in the world to think is in the
shower, don't you?
Anyway, I went into the shower this morning with this
question on my mind: "Why in the world would anyone
design a color bar that worked the way the IDL 8.1
Colorbar() function works?" Just because I can't
imagine doing it that way doesn't mean there isn't
some good reason for it. What could that reason be?
And then it hit me. Designing a color bar this is
way is *prefect* for displaying a single piece of
data! You take your data, byte scale it into 256
colors, and display it with the Colorbar() function.
Perfect. The color bar labels *exactly* reflect
the data, from minimum to maximum, exactly the way
you have meant them to be displayed.
What this color bar design is NOT good for is comparing
*two* pieces of data. For example, if I collected
sea ice data in June and I wanted to compare it to
sea ice data I collected in August, this color bar
design would be useless to me. I could display the
data side-by-side, each with its own perfectly correct
color bar. But, then I couldn't look at, say, a
red color in both images or contour plots and draw
any conclusions about what I was looking at! The two
data sets would be scaled differently.
How would someone who understands function graphics
better than I do approach the problem of displaying
two data sets, each with a different data range,
with a single color bar to explain the colors in
each?
Comparing data seems to me to be something that is
done rather frequently in the kind of work we do. :-)
Cheers,
David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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