Synopsis
		sfdipfilter < in.rsf > out.rsf dim=2 angle=n v=-1. ang1=-50. ang2=-45. ang3=45. ang4=50. v1=0. v2=0.1 v3=99999. v4=999999. pass=y

February 2014 program of the month:
http://ahay.org/blog/2014/02/06/program-of-the-month-sfdipfilter/

Parameters
		float ang1=-50.   float ang2=-45.   float ang3=45.   float ang4=50. Angle gate (in degrees)   bool angle=n [y/n] Filter based on angle (or velocity)   int dim=2 [2,3] Dimensionality: filter 2-D planes or 3-D cubes   bool pass=y [y/n] Pass or reject band   float v=-1. constant velocity (if angle-y) The default is d(frequency)/d(wavenumber)   float v1=0.   float v2=0.1   float v3=99999.   float v4=999999. Velocity gate

Used In
		DATA          alaska/line31-81-m8r   RSF          su/rsfdipfilt   SEP          fkamo/impresp oc2/ocimp   TCCS          nmo3/mcelroy scan3/realdata seislet/lena t2dweak/alaska