da_set_lc.inc

1 subroutine da_set_lc(proj)
2 
3    !-----------------------------------------------------------------------
4    ! Purpose: Initialize the remaining items in the proj structure for a
5    ! lambert conformal grid.
6    !-----------------------------------------------------------------------
7 
8    implicit none
9     
10    type(proj_info), intent(inout) :: proj
11 
12    real :: arg
13    real :: deltalon1
14    real :: tl1r
15    real :: ctl1r
16 
17    if (trace_use_dull) call da_trace_entry("da_set_lc")
18 
19    ! Compute cone factor
20    call da_lc_cone(proj%truelat1, proj%truelat2, proj%cone)
21    if (print_detail_map) then
22       write(unit=stdout, fmt='(A,F8.6)') 'Computed cone factor: ', proj%cone
23    end if
24    ! Compute longitude differences and ensure we stay out of the
25    ! forbidden "cut zone"
26    deltalon1 = proj%lon1 - proj%stdlon
27    if (deltalon1 .gt. +180.0) deltalon1 = deltalon1 - 360.0
28    if (deltalon1 .lt. -180.0) deltalon1 = deltalon1 + 360.0
29 
30    ! Convert truelat1 to radian and compute COS for later use
31    tl1r = proj%truelat1 * rad_per_deg
32    ctl1r = COS(tl1r)
33 
34    ! Compute the radius to our known lower-left (SW) corner
35    proj%rsw = proj%rebydx * ctl1r/proj%cone * &
36            (TAN((90.0*proj%hemi-proj%lat1)*rad_per_deg/2.0) / &
37             TAN((90.0*proj%hemi-proj%truelat1)*rad_per_deg/2.0))**proj%cone
38 
39    ! Find pole point
40    arg = proj%cone*(deltalon1*rad_per_deg)
41    proj%polei = 1.0 - proj%hemi * proj%rsw * Sin(arg)
42    proj%polej = 1.0 + proj%rsw * COS(arg)  
43    if (print_detail_map) then
44       write(unit=stdout,fmt='(A,2F10.3)') 'Computed pole i/j = ', proj%polei, proj%polej
45    end if
46 
47    if (trace_use_dull) call da_trace_exit("da_set_lc")
48 
49 end subroutine da_set_lc                             
50 
51