[fitsbits] reopening of Public Comment Period on the compression conventions

[Mark Taylor]

Ritchie,

thanks.  As far as java goes, if I attempt to implement this,
I will certainly look at stealing code from nom-tam-fits, so
your work should be valuable for me.

Mark

On Tue, 12 Jan 2016, van Nieuwenhoven, Richard wrote:

> Just a remark to the "burden of supporting tile-compressed FITS images"
> 
> While the first porting of all cfitsio (C programming language)
> compression code to nom-tam-fits (java programming language) was high.
> My estimate is that the whole port took me ~100 hours. But at least half
> of the time has gone in the outer design of the API -> clear separation
> of responsibilities, removing and detecting all code duplications and
> creating unidirectional code dependencies.
> 
> But now that there are two (free available) implementations of the fits
> compression, the next implementation should have a much easier job,
> implementing/porting them.
> 
> And as Bill stated implementations can always fall back on cfitsio and
> now also on nom-tam-fits if they don't want to implement the algorithms
> them self.
> 
> -Ritchie
> 
> Am 2016-01-11 um 23:25 schrieb William Pence:
> > I support the suggestion by Mark Taylor and Tom McGlynn to decouple the
> > Image compression and Table compression proposals so that they can each
> > be considered on their own merits.  I think it makes sense to discuss
> > them simultaneously during this public comment period, but when the time
> > comes, the proposals can be voted on separately.
> > 
> > FWIW, I strongly support incorporating the Image compression proposal
> > into the FITS Standard because it is an elegant and very effective
> > compression technique that has been used by many astronomical projects
> > for more than 25 years.
> > 
> > I also support the newer Table compression proposal, because I think it
> > is technically mature and it's feasibility has been demonstrated by one
> > major project (FACT).  While it is true that table compression is more
> > complicated than image compression, and the benefits are somewhat less
> > (in terms of compression ratios), and it is possible that in the future
> > we may think of further improvements to the table compression technique
> > (but these will not invalidate any FITS files that conform to the
> > current proposal), I don't think any of these reasons are strong enough
> > grounds to not approve this proposal now.
> > 
> > Finally, in response to Mark's remark about the burden that supporting
> > tile-compressed FITS images or tables could impose on software
> > developers, I would suggest a simpler solution in this case:  Just pipe
> > the compressed FITS file to an external uncompression program (funpack
> > in this case) and then process the output uncompressed FITS file as
> > usual.  Just as it usually is not cost effective to write one's own
> > software to directly read other compressed file formats (e.g., gzip or
> > bzip2) most existing FITS software does not need the capability to
> > directly read compressed FITS files and instead can rely on external
> > uncompression utility programs to do that job for them.
> > 
> > -Bill
> 
> 
> -- 
> BSc Richard van Nieuwenhoven
> Software Architekt
> 
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--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/