Topic:
What information do I get from Scan Tape?

Description:
Under IESX > DataManager > Load Seismic > SEGY Dump, there is an option to 
'Scan Tape'.  What information does it provide, and what is it typically 
used for?

Solution:
Scan Tape will read each record on tape, and report certain statistics for each
record.  It will direct it's output to either the screen, a file, or both.

The dump will look like this:

File number:       1 
Record number:       1 Number of bytes:    3200 
Record number:       2 Number of bytes:     400 
Record number:       3 Number of bytes:    8244 CDP     197121 SP     793737
Record number:       4 Number of bytes:    8244 CDP     197122 SP     793737
Record number:       5 Number of bytes:    8244 CDP     197123 SP     793737
Record number:       6 Number of bytes:    8244 CDP     197124 SP     793737
etc.

For file 1: (corresponding to the first line on a tape)
Record 1 contains 3200 bytes, which tells you it is the EBCDIC reel header.
Record 2 contains 400 bytes, and this corresponds to the binary line header.

Seismic traces start at Record 3. For seismic traces, Scan Tape reports:
Number of bytes in the trace (includes trace header and data).
CDP number (header words 21-24, IBM 32 bit floating point format).
Shotpoint number (header words 17-20, IBM 32 bit floating point format).

After Scan tape encounters a single End of File (EOF), it will report statistics
for File 2.  This continues until Scan Tape reaches a double EOF.


Typical uses:
   Scan tape is a good tool for quickly determining how many 2D lines are on 
   a tape, how many traces are in a 3D suvey (on one tape), or just to see if
   the correct Shotpoint and CDP are encoded in header words 17-20 and 21-24.




Last Modified on: 03-DEC-98