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subroutine da_set_merc(proj) 2,2
!--------------------------------------------------------------------------
! Purpose: Sets up the remaining basic elements for the mercator projection
!--------------------------------------------------------------------------
implicit none
type(proj_info), intent(inout) :: proj
real :: clain
if (trace_use) call da_trace_entry
("da_set_merc")
! Preliminary variables
clain = COS(rad_per_deg*proj%truelat1)
proj%dlon = proj%dx / (earth_radius_m * clain)
! Compute distance from equator to origin, and store in the
! proj%rsw tag.
proj%rsw = 0.0
if (proj%lat1 .NE. 0.0) then
proj%rsw = (alog(tan(0.5*((proj%lat1+90.)*rad_per_deg))))/proj%dlon
end if
if (trace_use) call da_trace_exit("da_set_merc")
end subroutine da_set_merc