anchor.diff:        IMPLICIT none
         REAL pi,r2d,d2r
         PARAMETER (pi=3.14159265,r2d=1.8e2/pi,d2r=pi/1.8e2)
  -      REAL lon1,lat1,lon2,lat2,colat1,colat2,dlon,dlat,a,arg
  +      REAL lon1,lat1,lon2,lat2,colat1,colat2,dlon,dlat,a
         REAL dist,az
   C----
   C Check if points are polar opposite
  
positive.code:       END
  
  c----------------------------------------------------------------------c
  
  
  
negative.code:       IMPLICIT none
        REAL*8 pi,r2d,d2r
        PARAMETER (pi=4.0d0*datan(1.0d0),r2d=1.8d2/pi,d2r=pi/1.8d2)
        REAL*8 lon1,lat1,lon2,lat2,colat1,colat2,dlon,dlat,a
        REAL*8 dist,az
  C----
  C Check if points are polar opposite
  