Synopsis
		sfpwd1 < in.rsf dip=dip.rsf > out.rsf left=y order=1 nj1=1 nj2=1 drift=n

Parameters
		file dip= auxiliary input file name   bool drift=n [y/n] if shift filter   bool left=y [y/n] if using left or right side of PWD   int nj1=1 in-line aliasing   int nj2=1 cross-line aliasing   int order=1 accuracy

Used In
		TCCS          apwd/crnfld apwd/trace