anchor.diff:  !=======+=========+=========+=========+=========+=========+=========+=========+
   
   subroutine search_next_polygon(xs, ys, xe, ye, x, y, current_polygon, next_polygon)
  -  use jcf_sphere_lib, only : is_cross_line
  +  use jcf_spherical_lib, only : get_intersection_point
     implicit none
     real(kind=8), intent(IN) :: xs, ys, xe, ye
     real(kind=8), intent(OUT) :: x, y
  
positive.code:   type(polygon_type), pointer :: next_polygon
    real(kind=8) :: x1, y1, x2, y2
    integer :: i1, i2
  
    do i1 = 1, current_polygon%num_of_point
      i2 = mod(i1, current_polygon%num_of_point) + 1
  
negative.code: !=======+=========+=========+=========+=========+=========+=========+=========+
  
  logical function is_in_this_polygon(x, y, polygon, is_lat_lon)
    use jcf_spherical_lib, only : is_inner
    implicit none
    real(kind=8), intent(IN) :: x, y
    type(polygon_type), intent(IN) :: polygon
  