'S1-RPAR.DAT: RAY PARAMETERS FOR INITIAL SURFACE.  1994, JANUARY 23.'

 2   -1   0   2       0.001   0.002   (ISRFR,ISRFX,ISRFY,NREC,XERR,AERR)
 20.   40.                            (XREC(1),XREC(2))

  0. -5.35534   60. 19.49747   0. 0.   20 0   1 /
/

------------------------------------------------------------------------

  ONE-PARAMETRIC SYSTEM OF RAYS FROM THE INITIAL SURFACE (E.G., FROM THE
  BOTTOM OF THE MODEL, OR FROM AN EXPLODING REFLECTOR) IS TRACED.
  THE RAY PARAMETERS G1,G2 ARE ASSUMED TO COINCIDE WITH CARTESIAN
  COORDINATES X1,X2.  THE RAYS ARE SHOT FROM THE INTERSECTION OF THE
  INITIAL SURFACE WITH THE VERTICAL PROFILE PASSING THROUGH THE POINT
  (X1,X2,X3)=(25,5,-25) AND MAKES AN ANGLE OF 22.5 DEG WITH THE X1X3
  COORDINATE PLANE.

========================================================================