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[fitsbits] Dataset identifications.
Thomas McGlynn writes:
My feeling is that if the two elements of data are so tightly coupled that they would normally be put in the same FITS file, then one would consider them to be the same dataset. At the HEASARC datasets generally comprise more than one FITS file. I can't think off the top of my head of an example where a given FITS file would naturally split up into multiple IDs. The need I had in mind is further down the line than either telescopes or places like HEASARC: an astronomer builds a single FITS file with all the images+photon-lists+tables+... that he uses in a given A&A paper, gives them a new DS_IDENT of course (probably derived from the bib code of the paper) in the primary header, and keeps the original DS_IDENT for each extension. Or actually, that merging might end up being done by the journals. It's a slight extension of what you proposed and it might perhaps never actually develop into reality, but I see no major reason to outright forbid that use. |
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[fitsbits] Dataset identifications.
Frankly, to avoid any confusion, I would advocate putting it in all
relevant headers, including the primary even when it is empty. - Arnold Mark Calabretta wrote: On Thu 2004/03/11 12:20:12 CDT, Thomas McGlynn wrote in a message to: Thierry Forveille and copied to: , one use of the IDs. However, I'm concerned that if a single FITS file is not atomic with respect to the dataset identifier, then it would generally be difficult for software to use the ID to tie things together. E.g., one would need to scan the entire FITS file to find the included IDs. Putting an index of IDs in the primary header, i.e. just a list of the IDs that come later, would preclude the need to scan past the first header when looking for a particular ID. Mark Calabretta ATNF _______________________________________________ fitsbits mailing list http://listmgr.cv.nrao.edu/mailman/listinfo/fitsbits -------------------------------------------------------------------------- Arnold H. Rots Chandra X-ray Science Center Smithsonian Astrophysical Observatory tel: +1 617 496 7701 60 Garden Street, MS 67 fax: +1 617 495 7356 Cambridge, MA 02138 USA http://hea-www.harvard.edu/~arots/ -------------------------------------------------------------------------- |
#13
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[fitsbits] Dataset identifications.
Frankly, to avoid any confusion, I would advocate putting it in all
relevant headers, including the primary even when it is empty. - Arnold Mark Calabretta wrote: On Thu 2004/03/11 12:20:12 CDT, Thomas McGlynn wrote in a message to: Thierry Forveille and copied to: , one use of the IDs. However, I'm concerned that if a single FITS file is not atomic with respect to the dataset identifier, then it would generally be difficult for software to use the ID to tie things together. E.g., one would need to scan the entire FITS file to find the included IDs. Putting an index of IDs in the primary header, i.e. just a list of the IDs that come later, would preclude the need to scan past the first header when looking for a particular ID. Mark Calabretta ATNF _______________________________________________ fitsbits mailing list http://listmgr.cv.nrao.edu/mailman/listinfo/fitsbits -------------------------------------------------------------------------- Arnold H. Rots Chandra X-ray Science Center Smithsonian Astrophysical Observatory tel: +1 617 496 7701 60 Garden Street, MS 67 fax: +1 617 495 7356 Cambridge, MA 02138 USA http://hea-www.harvard.edu/~arots/ -------------------------------------------------------------------------- |
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