Near Realtime processing aboard R/V Marcus Langseth

24 May 2008

Processing should be done on computer mcs as user sioseis, pw sioseis.
The bash .profile file has been set up with the necessary executable
and dynamic library search paths.  If all the underway sioseis processing
is done by user sioseis, then every watch can control the processing.
This is also done to minimize reading and writing across the net (/remote).
The sioseis executables are in /usr/local/sioseis/bin.
The sioseis scripts are in /usr/local/sioseis/scripts.
All the SEG-D shots are stored on /remote/nas/raw/SEGD
Recent SEG-D shots are also stored on  /remote/nas/working/MGLXXXX/stack
Sioseis output file should be kept on  /remote/nas/working/MGLXXXX/stack

As user sioseis, create directories under the sioseis home directory
for processing and copy the scripts from /usr/local/sioseis/scripts
to these local directories so that you can modify them as needed.

As done on Ewing, SIOSEIS near realtime (nrt) processing depends on
a script named    init    that creates a file /tmp/latest with the pathname
of the most latest two shots.  The script runs in an infinte loop and 
continually updates /usr/latest.  SIOSEIS process SEGDDIN continually
examines /usr/latest for new shots (parameter stack).

After modifying script init for the the appropriate cruise directory
name, it may be started before the beginning of shooting and left
running for the entire cruise (thus run it in background).

Script mklog creates a "master shot log" with a line for each shot
such as:
 file 144883 shot 144883 day  98 1938z  23.949 lat/long   9 47.9369  -88 20.8298
 WD  3386.5
The script   mklog   should be modified for the appropriate cruise
directory name.  Unfortunately, the Sun version does not allow a
"flush" after each write to the log, so the script should not be
terminated suddenly.  The Sun version does not append to the log
each time it starts - it writes over the previous file if it has the
same name.  The best way to terminate the mklog script is to use the
sioseis "infinite job" termination convention of creating a file
named     in     with the number   -1     in it.

Script    plot-shot    displays the "current" shot.  Sioseis generates 
a Sun rasterfile and displays it using xloadimage program (move 
around the plot by depressing the left mouse button and exit the
xloadimage by typing q in the plot).  If you are displaying the plot
on a computer other than mcs, type     xhost + mcs
The annotation at the top of the plot is the time of the shot.  The
annotation at the bottom of the plot is the last four digits of the shot
number and the trace number.  plot-shot is NOT dependent on script
init.

The brute stack script brute468 read the SEG-D files using the
method described for mklog above.  The script takes two arguments,
the line number/name and the plot direction (rtl or ltr).  There are
several outputs, with the main one being a plot file for the Atlantek
paper plotter, /remote/nas/working/MGL0810/stack/SEGY/$LINENO-stack.atlantek.
The plot file may be sent to the plotter by using program      atlantek
The script also creates file with the stacked data 
(/remote/nas/working/MGL0810/stack/SEGY/$LINENO-stack.segy)
A log file for the stack is also created
(/remote/nas/working/MGL0810/stack/SEGY/$LINENO-stack.log)