NAME:
  astlinks
 PURPOSE:
  Scan for linkages among a collection of asteroid astrometric measurements
 DESCRIPTION:

  This program looks for linkages between moving object astrometric
    measurements.  The main set of measurements that are scanned are all
    of the .ast files in the current directory.  These measurements are
    checked against all other objects in the same directory and against
    all objects in another directory.  The linkages are established by pure
    linear motion coincidence.

  There are two files written as the program runs, links.log and astlink.xrft.
    The file, links.log, is a copy of the copious information about each
    link that is written to the screen.  Here you get to see the data that
    lead up to the match.  The file, astlink.xrft, is a list of matches
    only.  It's in the same format as lplast.xrft which is used by ASTCOL to
    record the proper name in the output astrometry file.  If you have provided
    "otherdir" and there is an lplast.xrft file in that directory, that file
    is read and used to further resolve names.

 CATEGORY:
  Astrometry
 CALLING SEQUENCE:
  astlinks,otherdir
 INPUTS:

 OPTIONAL INPUT PARAMETERS:
  otherdir - If specified, the local .ast files are checked against this
               directory too.
 KEYWORD INPUT PARAMETERS:
  NOLOCAL - Flag, if set will suppress checking for linkages within the
               astrometry from the current directory.

  ONEFILE - Optional input of a single local .ast file to check against
               another directory.  Specifying this option implies /NOLOCAL.

 OUTPUTS:

 KEYWORD OUTPUT PARAMETERS:

 COMMON BLOCKS:

 SIDE EFFECTS:

 RESTRICTIONS:

 PROCEDURE:

 MODIFICATION HISTORY:
  98/01/13, Written by Marc W. Buie, Lowell Observatory
  2001/08/15, MWB, changed to use new rdlplast procedure.
  2002/09/03, MWB, changed Str_sep call to strsplit
  2004/9/21, MWB, removed obsolete call to Findfile