PROGRAM CLUSTER
 
                                         Programmer: Edward Carlson
                                         Converted By: Edward Carlson
                                         Last Update: 01/16/87
 
     A.  PURPOSE:
 
         To identify geodetic stations which are common to two data sets with
         respect to name or a given position tolerance.  Note: this program
         will accept a maximum of 1000 positions in either data set.
 
     B.  INPUT:
 
         1. Geodetic station records, retrieved from the NGS data
            base and stored on a floppy disk or in the main storage of
            the personal computer.  Note: If the geodetic positions
            are keyed from some other source, use the format given in
            Appendix A.
 
         2. User's Blue Book deck of geodetic positions, which is
            stored on a floppy disk or in the main storage of the
            personal computer.  The station records must follow the
            format given in Appendix A.
 
 
     C.  OUTPUT:
 
         1. A printed listing of clustered stations.
 
         2. A file of common stations from the data base, which are
            in the same format given in Appendix A.
 
     D.  METHOD:
 
         Program CLUSTER compares the user's geodetic station records
         from the Blue Book deck with the data base station records
         for an exact match by name or a match within a given
         tolerance by position.  If at least four different common
         points are not found by name or position the program will
         double the search area (1.414 * tolerance) iteratively until
         at least four different possible common points are found.
 
 
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     E.  EXECUTION:
 
          1. Load the program (CLUSTER.EXE) from the floppy disk to the
             main storage, or the program can be executed from a floppy disk
             drive.
 
          2. To execute the program:
 
            a. Type CLUSTER (hard disk) or (disk drive name):CLUSTER
               (floppy disk)
 
            b. The program will prompt for:
 
              1. Name of the data base file.
              2. Name of the Blue Book deck. (user's file)
              3. Name for the output file. (common points)
              4. Starting tolerance in seconds.
 
 
      F.  HELPFUL HINTS:
 
          1. Remove all blank records from the input files.
 
          2. For a paper listing, press Ctrl-PrtSc to turn the printer
             on when using an IBM PC instead of using the print option.
 
 
 
 
                   APPENDIX A
 
          Control Point Record (IE: *80* record) **
 
    CC01-06   Sequence Number                                (OPTIONAL)
    CC07-10   Data Code (IE: *80*)
    CC11-13   Station Serial Number                          (OPTIONAL)
    CC14      Blank
    CC15-44   Station Name
    CC45-55   Geodetic Latitude: Deg-Min-Sec, to 5 decimal places,
              decimal point implied between CC50-51 (DDMMSSsssss)
    CC56      Direction of Latitude:  N or S
    CC57-68   Geodetic Longitude: Deg-Min-Sec, to 5 decimal places,
              decimal point implied between CC63-64 (DDDMMSSsssss)
    CC69      Direction of Longitude:  E or W
    CC70-75   Elevation of mark above MSL, in meters, decimal
              point implied between CC73-74 (EEEEee)         (OPTIONAL)
    CC76      Elevation code                                 (OPTIONAL)
    CC77-78   State or Country Code                          (OPTIONAL)
    CC79-80   Station Order and Type                         (OPTIONAL)
 
 
    ** Format specified in the FGCC publication, Input Formats and
       Specifications of the National Geodetic Survey Data Base.
 
 
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