Program sftan2ang | tangent to angle transformation 
[SYNOPSIS]
sftan2ang < Fstk.rsf > Fang.rsf velocity=velocity.rsf na=nt da=90/(nt-1) a0=0. extend=4 top=n
[PARAMETERS]
float   | a0 | =0. |   | 	
float   | da | =90/(nt-1) |   | 	
int     | extend | =4 |   | 	tmp extension 
int     | na | =nt |   | 	
bool    | top | =n |  [y/n] | 	
file    | velocity | = |   | 	auxiliary input file name
[DIRECTORY]
system/seismic
