/ 
App-SeismicUnixGui-0.87.2
River stage zero No dependents
/ App::SeismicUnixGui::sunix::migration::sumigtk

SYNOPSIS

PERL PROGRAM NAME:

AUTHOR: Juan Lorenzo (Perl module only)

DATE:

DESCRIPTION:

Version:

USE

NOTES

Examples

SYNOPSIS

SEISMIC UNIX NOTES SUMIGTK - MIGration via T-K domain method for common-midpoint stacked data

 sumigtk <stdin >stdout dxcdp= [optional parms]			



 Required Parameters:							

 dxcdp                   distance between successive cdps		



 Optional Parameters:							

 fmax=Nyquist            maximum frequency				

 tmig=0.0                times corresponding to interval velocities in vmig

 vmig=1500.0             interval velocities corresponding to times in tmig

 vfile=                  binary (non-ascii) file containing velocities v(t)

 nxpad=0                 number of cdps to pad with zeros before FFT	

 ltaper=0                length of linear taper for left and right edges", 

 verbose=0               =1 for diagnostic print			



 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:								

 Input traces must be sorted by either increasing or decreasing cdp.	



 The tmig and vmig arrays specify an interval velocity function of time.

 Linear interpolation and constant extrapolation is used to determine	

 interval velocities at times not specified.  Values specified in tmig	

 must increase monotonically.						



 Alternatively, interval velocities may be stored in a binary file	

 containing one velocity for every time sample.  If vfile is specified,

 then the tmig and vmig arrays are ignored.				



 The time of first sample is assumed to be zero, regardless of the value

 of the trace header field delrt.					



 The migration is a reverse time migration in the (t,k) domain. In the	

 first step, the data g(t,x) are Fourier transformed x->k into the	",	

 the time-wavenumber domain g(t,k).					



 Then looping over wavenumbers, the data are then reverse-time		

 finite-difference migrated, wavenumber by wavenumber.  The resulting	

 migrated data m(tau,k), now in the tau (migrated time) and k domain,	

 are inverse fourier transformed back into m(tau,xout) and written out.",	





 Credits:

	CWP: Dave Hale



 Trace header fields accessed:  ns and dt

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 dxcdp

sub fmax

sub ltaper

sub nxpad

sub tmig

sub tmpdir

sub verbose

sub vfile

sub vmig

sub get_max_index

max index = number of input variables -1