FW: Discrete Fourier Transform (DFT) viewer and/or file format

Dan Hitt posted the following on the Debian user list. 
[https://lists.debian.org/debian-user/2017/11/msg00444.html].
I suggested he ask on comp.dsp .

> I have some DFTs that i wish to inspect.  (Apparently DFT is a common
> acronym, but here i mean Discrete Fourier Transform.  And properly
> speaking it doesn't make sense to inspect a transform, but only to
> inspect transformed data, but i'm speaking colloquially.)
>
> DFTs are a common artifact in digital signal processing.  Lots of
> Debian packages are focused on FFTs (Fast Fourier Transforms, a way of
> computing DFTs).  Nevertheless i couldn't find either a standard file
> format to store one, or software specifically for viewing DFTs.
>
> Of course, lots of software can take data, then transform it, then
> display the transform that it created, but i would like something that
> can take an already created DFT in some standard format, then display
> it.
>
> TIA for any information or pointers or advice from anybody! :)
>
> dan
>