Synopsis
		sfvelmod < scan.rsf > cmp.rsf half=y extend=4 slowness=n

Inverse of sfvscan.

Parameters
		int extend=4 trace extension   bool half=y [y/n] if y, the second axis is half-offset instead of full offset   bool slowness=n [y/n] if y, use slowness instead of velocity

Used In
		BEI          vela/vscan