On Tue, 15 Aug 2006, Mark Taylor wrote:
> > Hi Mark,
> >
> > Clive's right and GAIA uses the Skycat parsing for TAB tables. In Skycat
> > only the ra_col/dec_col and x_col/y_col parameters can be set to -1, the
> > id_col value must either have a column set, or it will use the first
> > column, regardless. The reason for this is nothing to do with any
> > standards (where they exist), just the practicalities of the
> > implementation which requires a column of identifiers for controlling row
> > selection (these should be unique but don't need to be just to get the
> > plotting to work). When possible during an import of a table without an
> > obvious identifier column I just create a simple integer index column.
>
> thanks - I'd figured that adding a new ID column where necessary was
> the best way round but it's nice to be reassured that -1 values are
> OK for ra_col and dec_col. Where I can't find an X/Y columns I just
> don't write x_col/y_col parameters rather than setting them -1,
> I presume that's OK.
Yes that will work, but there's no harm in adding the x_col: -1 and y_col:
-1 parameters anyway.
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