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Re: [Q]IDL: Using WHERE. [message #5962 is a reply to message #5958]

Thu, 21 March 1996 00:00

Paul Schopf
Messages: 2
Registered: March 1996

Junior Member

Thomas A. McGlynn wrote:

[snip, snip, snip]

> This is something that I've always wanted to be able to do efficiently
> but seem always to need to go through large arrays twice.
> I frequently run into the situation that I want to do one thing for

> with some bad pixels set to <0 and I want to display a logarithmic
> image of the data, I might want to do something like:
>
> w=where(image le 0)
> ww = where(image gt 0)
> qmin = min(image(ww))
> image(w) = .5*qmin
> tvscl,alog(image)
>

I know that this is not exactly what we are discussing here, but
how about

tvscl, alog( image > 0.5*min( image(where(image gt 0))) )

BTW, For Andy Loughe, note that we only ever need 1 line of
code, for maximum obfuscation. In this case if the where
statement fails, you are screwed anyway.

For Tom, I won't guarantee that this takes any less time.

--
Paul Schopf mailto://schopf@gsfc.nasa.gov
Coupled Climate Dynamics Group/971 http://ccdg.gsfc.nasa.gov/~paul
NASA Goddard Space Flight Center
Greenbelt, MD 20771

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[Message index]

		Re: [Q]IDL: Using WHERE. By: steinhh on Fri, 22 March 1996 00:00
		Re: [Q]IDL: Using WHERE. By: Paul Schopf on Thu, 21 March 1996 00:00
		Re: [Q]IDL: Using WHERE. By: Thomas A. McGlynn on Thu, 21 March 1996 00:00
		Re: [Q]IDL: Using WHERE. By: Mirko Vukovic on Wed, 20 March 1996 00:00
		Re: [Q]IDL: Using WHERE. By: rivers on Wed, 20 March 1996 00:00
		Re: [Q]IDL: Using WHERE. By: Andy Loughe on Tue, 19 March 1996 00:00

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