[AstroPy] Some Feedbacks about Astropy
Paul Kuin
npkuin at gmail.com
Thu Jul 3 14:30:39 EDT 2014
Dear Tom and Adam,
Those were convincing replies. I stand corrected. I learned some things
from your reply, however, as I need to check (again) flux conservation in
the Scipy routine I'm using. I checked a long time ago, but things get
'improved' sometimes the wrong way. I am thinking of getting on the dev
list just for the reason of knowing issues like this (though I see coding
more as a thing that comes with getting the science done than a thing in
itself.) I kind of felt bad for Guang Yang, who offered a piece of code he
wrote, and would not like to see him driven into using IDL. Some 25 years
ago I thought IDL was great, but with the commercialisation came problems
and I think one is better off with open source.
Another issue altogether is that it would be good to have the endorsement
of the IAU. At the moment the IAU is renewing itself, and I think the union
would benefit from having members involved who are both
astronomer/astrophysicist and software developer. I think that either of
you would benefit the community. Why do this? The IAU needs to go with the
times. Astropy is in much the same position for astronomy as FITS was in
the early 1990-ies. I think it gives visibility, focus, and legitimises
asking for support. At the moment the astronomical software is part of
Commission 5 (which is being revamped as everything else in the IAU), and
there are several software related things going on in other divisions.
Cheers,
Paul
On Thu, Jul 3, 2014 at 8:18 AM, Adam Ginsburg <adam.g.ginsburg at gmail.com>
wrote:
> I agree with Tom's points, but I'd also like to clarify that the
> variety of replies were not all to the same question.
>
> The scipy.map_coordinates+astropy.wcs, pyAST, and montage utilities
> that I, Ray, and Sophie mentioned solve the problem of image
> regridding and reprojection, which as Tom points out belongs in
> astropy-core eventually.
>
> The montage approach uses a wrapper to an underlying C program called
> montage that needs to be installed independently. The scipy approach
> is more purely python, but it requires interpolation and is not flux
> conserving (montage is). The pyAST approach wraps another underlying
> C library and implements its own resampling that can be flux
> conserving depending on certain flags chosen (but Dave Berry, correct
> me if I've gotten something wrong here):
> http://dsberry.github.io/starlink/node1.html#Resample
> http://www.starlink.rl.ac.uk/docs/sun210.htx/node371.html
> These routines could probably live in something called
> astropy.reprojection or something similar.
>
>
>
> The second class of problems addressed is image registration, which I
> think is being treated in ccdproc, SRPAstro, and the methods that Ray
> mentioned. I think these are each niche codes with a different role;
> image registration based on star matching is very different from that
> based on FFTs and extended emission matching. For a summary of the
> codes available for extended emission registration, have a look at
>
> http://image-registration.readthedocs.org/en/latest/#programs-implementing-these-methods-in-various-languages
> .
>
> I hope this is useful clarification, but please correct me if I
> misrepresented anyone's code here.
>
> On Thu, Jul 3, 2014 at 8:10 AM, Thomas Robitaille
> <thomas.robitaille at gmail.com> wrote:
> > Paul Kuin wrote:
> >> Reading all this, I think that part of the success of the IDL Astro
> >> library is due to having one head, Wayne Landsman, put it all together.
> >> This reads like a conversation on the tower of Babel. Everyone their own
> >> method. Someone should take the time to check and compare all the
> >> different implementations. Some funding for such work would be very
> >> useful and save on duplication. I think this is a task that the IAU
> >> could(should?) be involved in.
> >
> > Reducing duplication is precisely the goal of the Astropy project - in
> > fact, we have a rule that 'affiliated' packages should not duplicate
> > functionality from the core, and also avoid duplication amongst one
> > another. See the original vision document:
> >
> > http://docs.astropy.org/en/stable/development/vision.html
> >
> > If you are interested in getting involved, you can join the astropy-dev
> > mailing list. As part of the Astropy project, there have already been a
> > number of successes in merging existing packages to provide a core
> > implementation (for example the cosmology routines).
> >
> > On the more specific topic of re-projection - this is clearly a highly
> > requested feature, and I think it should be targeted as something that
> > should have an implementation in the core astropy package that then gets
> > used by all other packages.
> >
> > As a side note, the fact there was more than one reply to the original
> > question is a testimony to the strength of the development community in
> > Python - people are clearly not just waiting for one person to just
> > write it all. Yes, we need to all make an effort to not duplicate things
> > needlessly, but on the other hand, having two different ways of
> > approaching the same problem is not always bad.
> >
> > Cheers,
> > Tom
> >
> >> Paul
> >>
> >>
> >> On Wed, Jul 2, 2014 at 6:15 AM, Guang Yang <yg1991 at mail.ustc.edu.cn
> >> <mailto:yg1991 at mail.ustc.edu.cn>> wrote:
> >>
> >> Thank all of you for giving those advices. I think I won't bother to
> >> switch between python and IDL in my next project. ^^
> >>
> >> Best wishes,
> >> Guang
> >>
> >>
> >> -----Original email-----
> >> *From:* "Sofia Lianou" <slianou at uwo.ca <mailto:slianou at uwo.ca>>
> >> *Sent Time:* Jul 2, 2014 5:14:53 AM
> >> *To:* "Astronomical Python mailing list" <astropy at scipy.org
> >> <mailto:astropy at scipy.org>>, "Adam Ginsburg"
> >> <adam.g.ginsburg at gmail.com <mailto:adam.g.ginsburg at gmail.com>>
> >> *Cc:* "Pauline Barmby" <pbarmby at uwo.ca <mailto:pbarmby at uwo.ca>>
> >>
> >> *Subject:* Re: [AstroPy] Some Feedbacks about Astropy
> >>
> >> Hello,
> >>
> >> This is something that imagecube is doing, too, and the package
> >> is hosted here:
> >> http://sophiathl.github.io/imagecube/
> >>
> >> Beta release to follow soon, along with proper documentation.
> >>
> >> Cheers,
> >> Sophia, Pauline, and Jeff
> >>
> >> On 07/01/14, *Adam Ginsburg * <adam.g.ginsburg at gmail.com
> >> <mailto:adam.g.ginsburg at gmail.com>> wrote:
> >>> > 1. I find no tools to align two images, i.e. to uniform
> >>> their astrometry, pixel scale, image size and etc.
> >>> hastrom.pro <http://hastrom.pro>
> >>> (http://idlastro.gsfc.nasa.gov/ftp/pro/astrom/hastrom.pro) is
> >>> a good example to perform such a task.
> >>>
> >>> I've written a tool to do that:
> >>>
> https://github.com/keflavich/FITS_tools/blob/master/FITS_tools/hcongrid.py
> >>> ...I think it does what hastrom does, not hcongrid, which
> means I
> >>> should change the name.
> >>>
> >>> Otherwise, you can use the montage wrapper:
> >>> http://www.astropy.org/montage-wrapper/
> >>>
> >>>
> >>> --
> >>> Adam Ginsburg
> >>> Fellow, European Southern Observatory
> >>> http://www.adamgginsburg.com/
> >>> _______________________________________________
> >>> AstroPy mailing list
> >>> AstroPy at scipy.org <mailto:AstroPy at scipy.org>
> >>> http://mail.scipy.org/mailman/listinfo/astropy
> >>
> >>
> >>
> >> _______________________________________________
> >> AstroPy mailing list
> >> AstroPy at scipy.org <mailto:AstroPy at scipy.org>
> >> http://mail.scipy.org/mailman/listinfo/astropy
> >>
> >>
> >>
> >>
> >> --
> >>
> >> * * * * * * * * http://www.mssl.ucl.ac.uk/~npmk/ * * * *
> >> Dr. N.P.M. Kuin (n.kuin at ucl.ac.uk <mailto:n.kuin at ucl.ac.uk>)
> >> phone +44-(0)1483 (prefix) -204927 (work)
> >> mobile +44(0)7806985366 skype ID: npkuin
> >> Mullard Space Science Laboratory – University College London –
> >> Holmbury St Mary – Dorking – Surrey RH5 6NT– U.K.
> >>
> >> _______________________________________________
> >> AstroPy mailing list
> >> AstroPy at scipy.org
> >> http://mail.scipy.org/mailman/listinfo/astropy
> > _______________________________________________
> > AstroPy mailing list
> > AstroPy at scipy.org
> > http://mail.scipy.org/mailman/listinfo/astropy
>
>
>
> --
> Adam Ginsburg
> Fellow, European Southern Observatory
> http://www.adamgginsburg.com/
> _______________________________________________
> AstroPy mailing list
> AstroPy at scipy.org
> http://mail.scipy.org/mailman/listinfo/astropy
>
--
* * * * * * * * http://www.mssl.ucl.ac.uk/~npmk/ * * * *
Dr. N.P.M. Kuin (n.kuin at ucl.ac.uk)
phone +44-(0)1483 (prefix) -204927 (work)
mobile +44(0)7806985366 skype ID: npkuin
Mullard Space Science Laboratory – University College London –
Holmbury St Mary – Dorking – Surrey RH5 6NT– U.K.
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