=pod

=head1 NAME



B<funindex - create an index for a column of a FITS binary table>



=head1 SYNOPSIS





funindex <switches>  <iname> <key> [oname]





=head1 OPTIONS





  NB: these options are not compatible with Funtools processing. Please
  use the defaults instead.
  -c        # compress output using gzip"
  -a        # ASCII output, ignore -c (default: FITS table)"
  -f        # FITS table output (default: FITS table)"
  -l        # long output, i.e. with key value(s) (default: long)"
  -s        # short output, i.e. no key value(s) (default: long)"




=head1 DESCRIPTION




The funindex script creates an index for the specified column (key) by
running funtable -s (sort) and then saving the column value and the
record number for each sorted row. This index will be used automatically
 by funtools filtering of that column, provided the index file's modification
date is later than that of the data file.

 
The first required argument is the name of the FITS binary table
to index. Please note that text files cannot be indexed at this time.
The second required argument is the column (key) name to index. While
multiple keys can be specified in principle, the funtools index processing
assume a single key and will not recognize files containing multiple keys.


By default, the output index file name is [root]_[key].idx, where [root]
is the root of the input file. Funtools looks for this specific file name
when deciding whether to use an index for faster filtering. Therefore, the
optional third argument (output file name) should not be used for funtools
processing.


For example, to create an index on column Y for a given FITS file, use:

  funindex foo.fits Y

This will generate an index named foo_y.idx, which will be used by funtools
for filters involving the Y column.




=head1 SEE ALSO



See funtools(n) for a list of Funtools help pages


=cut
