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@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/