anchor.diff:    integer, intent(IN) :: div_num
     real(kind=8) :: point_pos_x, point_pos_y
     integer :: i, j, p
  -  real(kind=8) :: lat_diff, lon_diff
     type(polygon_type), pointer :: rect_polygon, target_polygon
     real(kind=8), dimension(div_num+1) :: x12, x23, x43, x14, y12, y23, y43, y14
     real(kind=8) :: x_pos(4), y_pos(4), x1, y1, x2, y2, x3, y3
     real(kind=8) :: px1, px2, px3, px4, py1, py2, py3, py4
  -  real(kind=8) :: x_diff, y_diff
   
     ! set rectangular polygon
     if (pa%num_of_point == 4) then ! rectangular polygon
  
positive.code: subroutine select_valid_side(ca, cb)
    implicit none
    type(coef_type), intent(INOUT) :: ca, cb
    integer :: i
  
    call check_both_point_in(ca)
    call check_both_point_in(cb)
  
negative.code:   character(len=*), intent(IN) :: coef_cal_type
    integer, intent(IN) :: side_div_num  
    type(polygon_type), pointer :: target_polygon
    real(kind=8) :: my_area
    real(kind=8) :: overlap_area, overlap_sum
    real(kind=8) :: point_x(MAX_POINT), point_y(MAX_POINT)
    real(kind=8) :: temp_coef
  