refer to: www.star.bris.ac.uk/~mbt/topcat/sun253/CdsUploadMatchWindow.html

The Match Parameters panel supplies the other information about how the match will operate:

• Radius

• The maximum distance between a local table and remote table position    to count as a match.  There is a maximum enforced on this value by    the CDS X-Match service, currently 2 arcminutes.

• Find mode

• Determines in what form the result is generated and used.    The following options are available:

  • Best

  • Load a new table with one row for each local row that matches        a remote row, giving the closest match.  Unmatched local rows        are not included.

  • All

  • Load a new table with one row for each remote row that matches        a local row.  The match is symmetric between local and remote tables.

  • Each

  • Load a new table with the same number of rows as the local table,        in the same order.  The best remote match, if any, appears alongside        the local row, but if there is no match the remote columns are blank.

  • Best Remote

  • Load a new table with one row for each remote table row that        matches the local table.        Note there is currently a bug in this mode;        if the match is done in N blocks then a remote row may appear        up to N times rather than just one.  This may be fixed in        a future release, but to avoid it you can make sure that the        Block size is greater than the row count.

  • Add Subset

  • No new table is loaded,        but a new Row Subset is added to the        local table indicating which rows had at least one match to the        remote table.