inpoly.F90

FUNCTION inpoly_complex2(x,y,n,xx,yy)
!-------------------------------------------------------------------------------
! Determines if a point xx,yy is inside a complex polygon
! defined by x(n),y(n),
! ref : https://wrfranklin.org/Research/Short_Notes/pnpoly.html
!
!-------------------------------------------------------------------------------
      implicit none
! arguments
      integer n
      real*8 x(n), y(n) , xx, yy
      logical inpoly_complex2
      integer i, j

      inpoly_complex2 = .false.
      j = n
      do i = 1, n
            if ( ((y(i) > yy) /= (y(j) > yy)) .and. &
                (xx < (x(j) - x(i)) * (yy - y(i)) / (y(j) - y(i)) + x(i)) ) then
                  inpoly_complex2 = .not. inpoly_complex2
            endif
            j = i
      enddo



END FUNCTION inpoly_complex2