Re: Image overlay

[Craig Markwardt <craigmnet(at)cow.physics.wisc.edu>]

raymond.pete@maine.edu (Raymond Pete) writes:

> Need some help here guys.. if u dont mind..
> 
> I have a Tire displayed using tv.. I also below that have an image file 
> that i have read in using a function i wrote to read a proprietarty image 
> extension displayed in a 2d section.. my issue is i want to overlay the 
> data image file onto the Tire to show the properties as such.. any 
> functions or advice would be GREATLY appreciated..
> 
> NOTE: the image file is setup as an 8-bit RBG file one byte per pixel..
> 

I see you posted twice, perhaps for effect.  What do you mean you have
a "Tire" displayed?  Is this the tread-frayin', Explorer-flippin',
lawsuit-makin' kind of tire?  Or some other kind of specialized data
plot?

If you want to overlay one image on another, that can be as easy or as
hard as you want it to be.  If you just have clusters of data then in
principle you can modify your original tire image using WHERE on your
data with a threshold.  I.e, 

wh = where(data GT 0)
tire(wh) = data(wh)   ;; Make this more complicated as needed

If you want something like transparent overlays that is a little
harder and probably involves a separate transparency channel.  Perhaps
somebodyt else can elaborate.

If you just want to overlay a coordinate system on an existing image,
then there are some good options.  My PLOTIMAGE will display an image
with coordinate axes, and you can even do XRANGE and YRANGE selection.
Liam Gumley's IMDISP does something similar.  Once you do that then
you can OPLOT symbols to your heart's content.

Craig

Markwardt IDL Page:
http://cow.physics.wisc.edu/~craigm/idl/idl.html   (under Graphics)

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Craig B. Markwardt, Ph.D.         EMAIL:    craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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