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Re: log scale of data coloring of IDLgrVolume object, not the axes [message #29021]

Wed, 30 January 2002 08:38

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Todd Bowers (tbowers0@yahoo.com) writes:

> Ok, I think I've figured out the whole log axis thing to get an
> IDLgrSurface axis to show log scale, its all about scaling the
> xyzCoord_Conv property of the surface with the logged bounds of your
> data.
>
> But, I'm having trouble carrying this over using log scale for the
> coloring of an IDLgrVolume object and the associated Hcolorbar from
> David F. (keeping the xyz axes linear, just logging the color ramp).
> Could anyone help?

HColorbar isn't designed for log scales, of course,
but I think it is just a matter of passing it a
color palette of values that have been scaled by
some kind of log function. For example:

r = BytScl(Findgen(256)^10e-2)
g = r
b = r
thePalette = Obj_New('IDLgrPalette', r, g, b)
theColorbar = Obj_New('HColorbar', Palette=thePalette)

Cheers,

David
--
David W. Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
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		Re: log scale of data coloring of IDLgrVolume object, not the axes By: David Fanning on Wed, 30 January 2002 08:38
		Re: log scale of data coloring of IDLgrVolume object, not the axes By: 1 on Fri, 08 February 2002 08:49

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