da_set_merc.inc

1 subroutine da_set_merc(proj)
2   
3    !--------------------------------------------------------------------------
4    ! Purpose: Sets up the remaining basic elements for the mercator projection
5    !--------------------------------------------------------------------------
6 
7    implicit none
8 
9    type(proj_info), intent(inout)       :: proj
10 
11    real :: clain
12 
13    if (trace_use) call da_trace_entry("da_set_merc")
14 
15    !  Preliminary variables
16 
17    clain = COS(rad_per_deg*proj%truelat1)
18    proj%dlon = proj%dx / (earth_radius_m * clain)
19 
20    ! Compute distance from equator to origin, and store in the 
21    ! proj%rsw tag.
22 
23    proj%rsw = 0.0
24    if (proj%lat1 .NE. 0.0) then
25       proj%rsw = (alog(tan(0.5*((proj%lat1+90.)*rad_per_deg))))/proj%dlon
26    end if
27 
28    if (trace_use) call da_trace_exit("da_set_merc")
29 
30 end subroutine da_set_merc
31 
32