SYNOPSIS

PERL PROGRAM NAME:

AUTHOR: Juan Lorenzo (Perl module only)

DATE:

DESCRIPTION:

Version:

USE

NOTES

Examples

SYNOPSIS

SEISMIC UNIX NOTES SUMIGSPLIT - Split-step depth migration for zero-offset data.

sumigsplit <infile >outfile vfile= [optional parameters]              



Required Parameters:                                                  

nz=                   number of depth sapmles                         

dz=                   depth sampling interval                         

vfile=                name of file containing velocities              



Optional Parameters:                                                  

dt=from header(dt) or .004    time sampling interval                  

dx=from header(d2) or 1.0     midpoint sampling interval              

ft=0.0                        first time sample                       

fz=                           first depth sample                      



tmpdir=        if non-empty, use the value as a directory path        

               prefix for storing temporary files; else if the        

               the CWP_TMPDIR environment variable is set use         

               its value for the path; else use tmpfile()             





Notes:                                                                

The input velocity file \'vfile\' consists of C-style binary floats.  

The structure of this file is vfile[iz][ix]. Note that this means that

the x-direction is the fastest direction instead of z-direction! Such a

structure is more convenient for the downward continuation type       

migration algorithm than using z as fastest dimension as in other SU  

programs.                                                     	



Because most of the tools in the SU package (such as  unif2, unisam2, 

and makevel) produce output with the structure vfile[ix][iz], you will

need to transpose the velocity files created by these programs. You may

use the SU program \'transp\' in SU to transpose such files into the  

required vfile[iz][ix] structure.                                     

(In C  v[iz][ix] denotes a v(x,z) array, whereas v[ix][iz]  		

denotes a v(z,x) array, the opposite of what Matlab and Fortran	

programmers may expect.)						", 



 



Credits: CWP Baoniu Han, July 21th, 1997



Reference:

 Stoffa, P. L. and Fokkema, J. T. and Freire, R. M. and Kessinger, W. P.,

 1990, Split-step Fourier migration, Geophysics, 55, 410-421.





Trace header fields accessed: ns, dt, delrt, d2

Trace header fields modified: ns, dt, delrt

User's notes (Juan Lorenzo) untested

CHANGES and their DATES

Import packages

instantiation of packages

Encapsulated hash of private variables

sub Step

collects switches and assembles bash instructions by adding the program name

sub note

collects switches and assembles bash instructions by adding the program name

sub clear

sub dt

sub dx

sub dz

sub ft

sub fz

sub nz

sub tmpdir

sub vfile

sub get_max_index

max index = number of input variables -1