These data were recorded in 2010 on a Geometrics with a GPS attached.
     There's a timing issue with recording the NMEA nav string in the
SEG-D External header.  The number of external headers in wrong in the SEG-D
General Header on 197.sgd.  The number of bytes in external header is wrong
on 200.sgd as well as the number of external headers.
     Geometrics corrected the problem (unsure of when).


197.sgd - General header says 2 External headers, but there are 3
019780580000000000001011460929350000000000000800008FFF002000002   General Header #1.
                              upper part of byte 12 says 1 additional general header
                              byte 29 says 2 channel sets
                              Byte 32 says 2 external headers

000000000000000000000100000000119400020000000000000000000F224638   General Header #2
0101000008CA0000004810031000002400000000000000000000000000010000   Channel set descriptor #1
0102000208CA0000000070031000002400000000000000000000000000010000   Channel set descriptor #2
2447504747412C3039313631302E30302C333934302E3238373432302C4E2C30   External header #1
 $ G P G G A , 0 9 1 6 1 0 . 0 0 , 3 9 4 0 . 2 8 7 4 2 0 , N , 0

373035312E3138333131392C572C322C392C302E392C352E3030342C4D2C2D33   External header #2
 7 0 5 1 . 1 8 3 1 1 9 , W , 2 , 9 , 0 . 9 , 5 . 0 0 4 , M , - 3
342E30312C4D2C332C3139392A35460D0A000000000000000000000000000000   External Header #3
 4 . 0 1 , M , 3 , 1 9 9 * 5 F

019701010010000000096000000000100000000                            trace header
          BE0A710C BE0A710C BE0A710C BE0A710C                      DATA
 BE0A710C BE0A710C BE0A710C BE0A710C BE0A710C
 BE0A710C BE0A710C BE0A710C BE0A710C BE0A710C
 BE0A710C BE0A710C BE0A710C BE0A710C BE0A710C



201.sgd - General header says 6 External headers, but several fewer
020180580000000000001011460929590000000000000800008FFF0102000006 General #1
000000000000000000000100000000119400020000000000000000000F224638 General #2
0101000008CA0000004810031000002400000000000000000000000000010000 Chan set desc #1
0102000008CA0000000070031000002400000000000000000000000000010000 Chan set desc #2
2447504747412C3039313633332E30302C333934302E3237383133382C4E2C30 External 1
 $ G P G G A , 0 9 1 6 3 3 . 0 0 , 3 9 4 0 . 2 7 8 1 3 8 , N , 0
373035312E3231353237352C572C322C392C302E392C322E3830322C4D2C2D33 External 2
 7 0 5 1 . 2 1 5 2 7 5 , W , 2 , 9 , 0 . 9 , 2 . 8 0 2 , M , - 3
342E30312C4D2C342C3139392A35450D0A000000000000000000000000000000 External 3
 4 . 0 1 , M , 4 , 1 9 9 * 5 F
000000000000000000000000000000
                              0201010100010000000096000000000000 External 4
                               ^start of trace header
0000004119AB474119AB474119AB474119AB474119AB474119AB474119AB4741 External 5
      ^Start of data
 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741 External 6
 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741 19AB4741
 19AB4741 19824241 18CB3741 174D4541 15BA6C41 159D0341 14EEDF41 14572D41
 14D2A041 1448DC41 131AA141 120ED741 116F6741 112B4C41 11081541 10F2CC41
 10A2B141 1028CB41 0FAC3041 0F86A641 0F8D9E41 0F8B4B41 0F4B0E41 0E91B141
 0DD7F141 0DB51D41 0E25BA41 0E091741 0D2A9441 0C2FD141 0B0BA541 0A1ED141
 08A9C441 07FF7F41 07938841 06594E41 07209941