Re: Can this be done using CALL_FUNCTION?

[edward.s.meinel(at)aero.org]

In article <38C53FCA.A89BD43E@astro.cornell.edu>,
  "J.D. Smith" <jdsmith@astro.cornell.edu> wrote:
> edward.s.meinel@aero.org wrote:
>>
>>I am working with spectral images. Unfortunately, IDL is geared toward
>>multidimensional data in which all of the dimensions are the same type
>>(i.e. spatial, spectral, frequency...) but it doesn't like to operate
>>on data with mixed dimensions, such as a multispectral image.
>
> What is it about multi-spectral data that IDL doesn't like?

You answered your own question...

>It's up to
> you to keep track of which dimensions are which,

This gets to be a real pain after the umpteenth time of checking the
number of dimensions and setting up the different cases of TRUE.

>It certainly
>doesn't care about whether a single dimension of your data array
>represents spatial, temporal, or spectral changes...
>maybe I'm missing something.

No, IDL doesn't care about these issues when _creating_ the array, but
it certainly does care when _operating_ on the array.

>It is true that certain IDL routines operate on images, or require
>other specially formatted or dimensioned data, but how is it to know
>which dimensions you are interested in without specifically telling it?

Well, I was thinking about something along the lines of the example I
gave.

> Maybe you could give us an example in which this kind of generality
> would be useful.

I did. How about HISTOGRAM? FFT? Median filter? ...

Ed Meinel


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