anchor.diff:        CHARACTER*40 ofile
         CHARACTER*200 clip
         REAL*8 x1,x2,y1,y2,dx,dy,dz,dd,ref(5),dist,az,lo,la
  -      REAL*8 x,y,z,xx(1000),yy(1000),zsave
  +      REAL*8 x,y,z,xx(1000),yy(1000),zsave,tmp
         INTEGER i,j,nx,ny,p,xsec,xz,nn,io
   
   C----
   C Get parameters from the command line
  +C     x1:    First defined x value (default: 0)
  +C     x2:    Second defined x value (default: 0)
  +C     nx:    Number of x increments (default: -1)
  +C     dx:    x increment, overrides nx (default: -1.0)
  +C     y1:    First defined y value (default: 0)
  +C     y2:    Second defined y value (default: 0)
  +C     ny:    Number of y increments (default: -1)
  +C     dy:    y increment, overrides ny (default: -1.0)
  +C     z:     z value
  +C     ofile: Name of output file
  +C     p:     Standard output flag (default: 0)
  +C     ref:   
  +C     xsec:  
  +C     xz:    
  +C     clip:  
   C----
         call gcmdln(x1,x2,nx,dx,y1,y2,ny,dy,z,ofile,p,ref,xsec,xz,clip)
   C Check that limits and increments are properly defined
  
positive.code:           ENDIF
            INOUT=-INOUT
            GOTO 2
  3         IF ((Y(I)*X(J)-X(I)*Y(J))/(X(J)-X(I))) 2,4,5
  4         INOUT=0
            RETURN
  5         INOUT=-INOUT
  
negative.code:       INOUT=-1
        DO 2 I=1,N
            J=1+MOD(I,N)
            MX=X(I).GE.0.0 ! Is the point on the clipping path east of the point of interest?
            NX=X(J).GE.0.0 ! Is the next point on the clipping path east of the point of interest?
            MY=Y(I).GE.0.0 ! Is the point on the clipping path north of the point of interest?
            NY=Y(J).GE.0.0 ! Is the next point on the clipping path north of the point of interest?
            IF(.NOT.((MY.OR.NY).AND.(MX.OR.NX)).OR.(MX.AND.NX)) THEN
                GOTO 2
            ENDIF
  