[AstroPy] Co-ordinating Python astronomy libraries?

Wolfgang Kerzendorf wkerzendorf@googlemail....
Fri Jul 16 08:38:50 CDT 2010


  Looking forward to that. I'm wondering if PyWCS should be able to read 
wavelength solutions (I think they could be considered WCS as well).

I have always wrapped wcstools (in a very crude way by calling them on 
the command line) and I found that they could handle nearly anything. I 
know they are under GPL and Mike D. regarded this as a problem. Is it 
still a problem?

Cheers
    Wolfgang
On 16/07/10 2:35 PM, Perry Greenfield wrote:
> I'd like to tackle the WCS issue first since there are already several 
> flavors out there and I really wonder if that is necessary. Mike 
> Droettboom is going to take a look at the others and see what the 
> differences are in the next week. It would be good to get some 
> convergence on that.
>
> But I don't think that can stop others from surveying and comparing 
> what is out there with regard to coordinates or time.
>
> As far as the pure python aspect goes, I don't know if I would be so 
> definitive on that. If there is already a good time or coordinates 
> library in C that has been very well tested, it might make sense to 
> use that. It isn't usually a big deal to distribute C code if it has 
> no other dependencies. Fortran is a different issue. And there are 
> many tricky issues with regard to coordinate systems. If reimplemented 
> in  pure python I'd suggest that we do a exhaustive test comparison 
> (mostly automatically generated if possible) with a well tested 
> library to make sure that it was well validated.
>
> Perry
>
> On Jul 16, 2010, at 5:01 AM, Wolfgang Kerzendorf wrote:
>
>>  Hello guys,
>>
>> I think astropysics looks like a very good start for the coordinate 
>> class.
>> As you said we should at the moment focus on having python-only classes
>> for the base-level. That makes it easy to distribute. Once a good API
>> has been established and there's complaints about speed, we can switch
>> over to c or fortran implementations with the same API.
>>
>> A monolithic distribution is not so good. I think these baselevel
>> classes should, be very modular. We can probably achieve the best
>> exceptance when these base classes are lean and mean. Like the unix
>> tools, each one of them should only provide a very limited set of
>> functionality. A good start might be pyAstroTime and pyAstroCoords or
>> so. That's where raiding and plundering the existing code base comes in.
>> We can use some of Erik's and Brandon's stuff and others. I think we can
>> easily make a working prototype and the build from there.
>>
>> As suggested, we need to be careful not to ignore anyone. But I think
>> that's easily done by making groups from this community, that take care
>> of a single implementation. Everyone who's interested in contributing,
>> can join. That way the workload is shared and it is build by the
>> community for the community.
>>
>> What do you guys think?
>>
>> Cheers
>>     Wolfgang
>



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