SUMUTE - mute above (or below) a user-defined polygonal curve with	", 
	   the distance along the curve specified by key header word 	

 sumute <stdin >stdout xmute= tmute= [optional parameters]		

 Required parameters:							
 xmute=		array of position values as specified by	
 			the `key' parameter				
 tmute=		array of corresponding time values (sec)	
 			in case of air wave muting, correspond to 	
 			air blast duration				
  ... or input via files:						
 nmute=		number of x,t values defining mute		
 xfile=		file containing position values as specified by	
 			the `key' parameter				
 tfile=		file containing corresponding time values (sec)	

 Optional parameters:							
 key=offset		Key header word specifying trace offset 	
 				=tracl  use trace number instead	
 ntaper=0		number of points to taper before hard		
			mute (sine squared taper)			
 mode=0		=1 to zero BELOW the polygonal curve		
        		=2 to mute below AND above a straight line	
 			in that case xmute,tmute describes the total	
			time length of the muted zone			
 linvel=330   		linear velocity					
 tm0=0   		time shift of linear mute at \'key\'=0		


 Notes: 								

 The tmute interpolant is extrapolated to the left by the smallest time
 sample on the trace and to the right by the last value given in the	
 tmute array.								

 The files tfile and xfile are files of binary (C-style) floats.	

 In the context of this program "above" means earlier time and	
 "below" means later time (above and below as seen on a seismic section.

 The below=2 option is intended for removing air waves. The mute is	
 is over a narrow window above and below the polygonal line specified	
 by the values in tmute, xmute or tfile and xfile.			

 If data are spatial, such as the (z-x) output of a migration, then    
 depth values are used in place of times in tmute and tfile. The value 
 of the depth sampling interval is given by the d1 header field	

 Caveat: if data are seismic time sections, then tr.dt must be set. If 
 data are seismic depth sections, then tr.trid must be set to 30, and  
 tr.d1 header field must be set.					


 Credits:

	SEP: Shuki Ronen
	CWP: Jack K. Cohen, Dave Hale, John Stockwell
	DELPHI: Alexander Koek

 Trace header fields accessed: ns, dt, delrt, key=keyword, trid, d1
 Trace header fields modified: muts or mute