[Ifeffit] Re: Ifeffit Digest, Vol 22, Issue 1

[Bruce Ravel]

On Wednesday 01 December 2004 06:01 pm, Carlo U. Segre wrote:
> On Wed, 1 Dec 2004, Bruce Ravel wrote:
> > I agree that it's a fool's game trying to stay on top of every single
> > goofy format that too-clever-by-half DAQ software programmers have
> > come up with.  Much better than that would be to suggest standards for
> > an exafs data file format.  At this late date, we have a pretty good
> > grasp of the technology involved in exafs measurements and so we know
> > what needs to be in the file.  If someone -- say the International
> > XAFS Society -- were to publish a standard, it would provide guidance
> > that would benefit the programmers of DAQ software, of analysis
> > software, and of any tools to link the two.
>
> Bruce:
>
> I agree with this notion.  The file format we use has been loosely
> patterned after other beamline's formats.  Perhaps it would be good to
> define a set of rules for a self-documenting file format plus a minimal
> set of information whcih needs to be present in the file.  Then different
> beamlines can just add what they like in terms of additional documentation
> or details specific to the line.
>
> Carlo

I actually had something even simpler in mind as a starting point.
Things like:

(1) A clear distinction between header and data (my preference would
    be an non-alphanumeric leading character for the header)
(2) Data in columns
(3) Nothing after the data
(4) The data in the columns should consist entirely of floats
(5) The last line of the header should contain white-space-separated
    column labels so the user can know what data is in which column

Many beamlines already do those things, but I can think of examples of
beamlines that do not do numbers 1, 4, and 5.

Of course there are other cans of worms -- locale for example -- that
could be addressed.  But even a minimal set of guidelines would be
helpful, IMHO.  Other communities, the crystallographers for instance,
have benefited by standardization of data exchange formats.

B


-- 
 Bruce Ravel  ----------------------------------- ravel at phys.washington.edu
 Code 6134, Building 3, Room 405
 Naval Research Laboratory                          phone: (1) 202 767 2268
 Washington DC 20375, USA                             fax: (1) 202 767 4642

 NRL Synchrotron Radiation Consortium (NRL-SRC)
 Beamlines X11a, X11b, X23b
 National Synchrotron Light Source
 Brookhaven National Laboratory, Upton, NY 11973

 My homepage:    http://feff.phys.washington.edu/~ravel 
 EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/