subroutine cartint
	use define
	implicit none

!       Bi-linear interpolation of cylindrical grid to cartesian grid

        do j=1,gps
        do i=1,gps

        ifound = 0

        reta = 2.*pi + atan2(yy(j),xx(i))  	!radians

        if (reta .gt. 2*pi) then
        reta = reta - 2*pi
        endif

        radius = (xx(i)**2 + yy(j)**2)**0.5   	!km

!       Searching cylindrical grid for first cartesian point

        do ia=1,nl
        do ir=1,np

	rds1 = ir*res			!km
	rds2 = (ir+1)*res		!km			

!	Coordinate system defined so 0/360 is to the right...180---x---0

	if (ia .lt. nl) then
	raz1 = ia*da*pi/180.		!radians
	raz2 = (ia+1)*da*pi/180.	!radians
	else if (ia .eq. nl) then
	raz1 = 0.			!radians
	raz2 = da*pi/180.            	!radians
	endif

!       Bracket point in x and y then do weighted bi-linear interpolation

	if (ia .eq. nl) then	
	iaz = 1
	else 
	iaz = ia+1	
	endif 

	if (rds1 .le. radius .and. rds2 .ge. radius .and. raz1 .le. reta .and. raz2 .ge. reta) then

!	print*,rds1,radius,rds2
!	print*,raz1,reta,raz2

!	radial weights

        wght_lft = 1 - (abs(radius - rds1)/res)
        wght_rgt = 1 - (abs(radius - rds2)/res)

	bot(:) = wght_lft*field_polar(ir,ia,:) + wght_rgt*field_polar(ir+1,ia,:)
	top(:) = wght_lft*field_polar(ir,iaz,:) + wght_rgt*field_polar(ir+1,iaz,:)

!	azimuthal weights

	wght_bot = 1 - (abs(raz1 - reta)/(da*pi/180.))
	wght_top = 1 - (abs(raz2 - reta)/(da*pi/180.))

        cart(i,j,:) = wght_bot*bot(:) + wght_top*top(:)

!	print*,'wind'
!	print*,wc(ir,ia,k),wc(ir+1,ia,k),wc(ir,iaz,k),wc(ir+1,iaz,k)
!	print*,ci,cj,cart(ci,cj,k)
	ifound = 1

        endif

	if (ifound .eq. 1) then
	goto 100
	endif

        enddo
        enddo

	if (ifound .eq. 0) then
	cart(i,j,:) = 0.
	endif

100	continue

	enddo
	enddo

	return
	end