[AstroPy] specutils, pyspeckit, etc.

[Adam]

(apologies for the subject and my delay in replying, I have been
receiving astropy-users e-mails in digest form and have missed nearly
everything.  So this e-mail is also a vote to move to
astropy-users at google)

As Erik said, it's best to merge these parallel efforts and try to
develop one common package with a nice interface.  My vision for the
future of pyspeckit is essentially to have it be a wrapper of
specutils + astropy.models + astropy.units, and in fact my current
coding effort is mostly going in that direction (see, e.g.,
spectroscopic equivalencies in astropy).  I wanted to raise it as an
example of something that works *right now*, but doesn't work
perfectly (as Jonathan rightly pointed out).  Most of the models
implemented in pyspeckit should be very easy to re-write as
astropy.models... models.  That goal, in particular, is a big
component of one of the specutils SOCIS proposed projects.

Also, pyspeckit's frontend is matplotlib-only, which is slow but
compatible with everything.  Because it's matplotlib-only, and
matplotlib doesn't have a ton of GUI features (more than you'd think,
fewer than you need), the GUI side is very IRAF-splot-like.

Re: Jonathan - pyspeckit does all those things.  If you want them
interactively, have a look at this example:
pyspeckit.readthedocs.org/en/latest/interactive.html
That said, the GUI interface really is not the best - it's not what I
want, but it is what is possible with matplotlib right now.  A
summer-of-code student could, I think, turn my half-assed GUI into a
real one (for specutils).  If anything in particular is missing that
you *really* want, though, I'm happy to try to support it in pyspeckit
now, with the idea of porting it to specutils once things come
together.

Re: Kelle - I think pyspeckit can do anything splot can at this point,
though I'm not so sure about spectral indices.  Ratios should be
easy...

I think there is a lot to be learned from pyspeckit (and Erik's
pymodelfit/astropysics) when developing specutils, some of which will
just be "lessons learned" (GUI features?) but other components that
can really be reused code (especially the models).

-- 
Adam