da_llxy_merc_new.inc

1 subroutine da_llxy_merc_new(proj, info)
2 
3    !-----------------------------------------------------------------------
4    ! Purpose: Compute x/y coordinate from lat lon for mercator projection
5    !-----------------------------------------------------------------------
6   
7    implicit none
8 
9    type(proj_info), intent(in)    :: proj
10    type(infa_type), intent(inout) :: info
11 
12    real :: deltalon
13    integer :: n
14 
15 if (trace_use) call da_trace_entry("da_llxy_merc_new")
16 
17 ! FAST
18 
19 !   where (lon(:,:) - proj%lon1 < -180.0)
20 !      x(:,:) = 1.0 + (lon(:,:) - proj%lon1 + 360.0)/(proj%dlon*deg_per_rad))
21 !   elsewhere (lon(:,:) - proj%lon1 > 180.0)
22 !      x(:,:) = 1.0 + (lon(:,:) - proj%lon1 - 360.0)/(proj%dlon*deg_per_rad))
23 !   else
24 !      x(:,:) = 1.0 + (lon(:,:) - proj%lon1)/(proj%dlon*deg_per_rad))
25 !   end where
26 
27 !   y(:,:) = 1.0 + (ALOG(TAN(0.5*((lat(:,: + 90.0) * rad_per_deg)))) / proj%dlon - proj%rsw
28 
29 ! SLOW
30 
31    do n=lbound(info%lat,2),ubound(info%lat,2)
32       deltalon = info%lon(1,n) - proj%lon1
33       if (deltalon < -180.0) deltalon = deltalon + 360.0
34       if (deltalon > 180.0) deltalon = deltalon - 360.0
35       info%x(:,n) = 1.0 + (deltalon/(proj%dlon*deg_per_rad))
36       info%y(:,n) = 1.0 + (ALOG(TAN(0.5*((info%lat(1,n) + 90.0) * rad_per_deg)))) / proj%dlon - proj%rsw
37    end do
38 
39 if (trace_use) call da_trace_exit("da_llxy_merc_new")
40 
41 
42 end subroutine da_llxy_merc_new
43 
44