SIOSEIS scripts to remove the ship heave and filter agc and plot.

        Heave Removal Using User Picked Water Bottom Times

                 Threshold Picker


This method of heave removal uses the difference between
the automatic first break pick and the smoothed automatic
first break pick.  The first break pick uses the first sample
value (amplitude) that exceeds 5000.  The SOLRAT picker used
in the previous examples seemed to have some pings that were
out of phase (pi or 180 degrees).  Prout (sets .190 .240) was
used to examine the amplitudes on a few pings.

This procedure has to be done in two steps because process 
HEADER has to be used twice.

1)  Step 1 uses the automatic picker in process WBT to pick the
    first arrival and put it in SEG-Y header word 50.  Process
    HEADER then copies header word 50 to word 59 and process
    DISKOA writes the file to disk.

2)  Step 2 uses process MIX to average header word 59.  Process 
    HEADER subtracts header word 50 from header word 59 and puts
    the result in header word 60.  Process SHIFT shifts the
    trace by the amount in header word 60.

    There are several new MIX parameters introduced for this 
    process.  TYPE 4 mix means to mix the header only and NOT
    to mix the seismic data.  Parameters HDR, LHDR, IHDR 
    indicates the index of the SEG-Y word to mix.

sioseis << eof1
procs diskin filter wbt header diskoa end
diskin
   fno 469 lno 1475 allno no set .190 .240
   ipath L001_001.anal end
end
filter
   fno 1 lno 99999 pass 500 2000 ftype 0 end
end
diskoa
   opath L001_001.heave end
end
wbt
       thres 5000 end
end
header
   fno 0 lno 99999 r59 = r50 end
end
end
eof1

sioseis << eof2
procs diskin mix header shift agc plot end
diskin
   ipath L001_001.heave end
end
agc
   winlen .01 end
end
mix
   type 4 hdr 59 weight  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
   1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 end
end
header
   fno 0 lno 99999 ftr 0 ltr 99 r60 = r59 - r50 end
end
shift
   fno 0 lno 99999 indices r60 end
end
plot
   wiggle 0  ann gmtint anninc 1
   trpin 150 def .008  tlines .001
   srpath sunfil
  nibs 2859 nsecs .04 vscale 75.75758
   end
end
end
eof2
xloadimage -r 90 sunfil &