proposal to turn the tables
womullan at skysrv.pha.jhu.edu
Tue Apr 29 06:28:54 PDT 2003
I think using DIME is a much better way of attaching images to VOTable than
trying to stuff them in a cell. Why reinvent this ?
Of course the simple solution to the string problem is to delineate each string with <string></string>....
It seems we are trying to make XML efficient and therby not ending up with xml anymore. XML is not efficient - it can be greatly compressed and we may use DIME to attach binary objects.
I am sure we shall have extended discussions in Cambridge on this ...
On Tue, Apr 29, 2003 at 01:44:26AM +0200, Francois Ochsenbein wrote:
> Well, again NaN applies to numbers (and floating-point numbers only) --
> it does not solve the problem of strings... As Ed pointed out, an
> empty string (which is not theoretically identical to a NULL string)
> cannot be coded without further conventions in the transposed scheme.
> Looking in the various comments also leads to ask the question about a
> string data type in VOTable... Currently, as Roy pointed out, a string
> is an array of bytes, as it is in FITS... Any comment / suggestion ?
> It also seems that images could become an important item in VOTables
> (e.g. as the results of VOQueries). Should also sunc a datatype be added
> there -- or would the "blob" concept (binary large object -- obviously
> encoded) be enough for results of VOQueries ?
> See you in the near future !
> >> The nil would require a noData attribute as I believe that, in elements,
> >> double spaces get normalized to a single space. Since bit data takes
> >> only 0 and 1 one would not have a nil there. One could change bitList
> >> to takes -1,0,1 and use -1 for nil. But, I don't think that bit data
> >> needs this much. Perhaps we could have an additional type: bitsyType.
> >Most reasonable software allows the use of "NaN" for nil without trying to
> >interpret it as a string among numbers. (Th softwares then normally
> >discard that entire row when trying to plot from the table). We could perhaps
> >replace nils by NaNs if the tables are to be turned on their side. I do
> >not know how the current VOtable browsers deal with NaNs though.
> >Ashish Mahabal, Caltech Astronomy, Pasadena, CA 91125
> >http://www.astro.caltech.edu/~aam aam at astro.caltech.edu
> >RAM DISK is not an installation procedure!
> Francois Ochsenbein ------ Observatoire Astronomique de Strasbourg
> 11, rue de l'Universite F-67000 STRASBOURG Phone: +33-(0)390 24 24 29
> Email: francois at astro.u-strasbg.fr (France) Fax: +33-(0)390 24 24 32
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