91 lines
2.5 KiB
Fortran
91 lines
2.5 KiB
Fortran
c****************************************************************
|
|
subroutine latlon(elp,r_v,r_llh,i_type)
|
|
|
|
c****************************************************************
|
|
c**
|
|
c** FILE NAME: latlon.f
|
|
c**
|
|
c** DATE WRITTEN:7/22/93
|
|
c**
|
|
c** PROGRAMMER:Scott Hensley
|
|
c**
|
|
c** FUNCTIONAL DESCRIPTION:This program converts a vector to
|
|
c** lat,lon and height above the reference ellipsoid or given a
|
|
c** lat,lon and height produces a geocentric vector.
|
|
c**
|
|
c** ROUTINES CALLED:none
|
|
c**
|
|
c** NOTES: none
|
|
c**
|
|
c** UPDATE LOG:
|
|
c**
|
|
c****************************************************************
|
|
|
|
implicit none
|
|
|
|
c INPUT VARIABLES:
|
|
integer i_type !1=lat,lon to vector,2= vector to lat,lon
|
|
c structure /ellipsoid/
|
|
c real*8 r_a
|
|
c real*8 r_e2
|
|
c end structure
|
|
c record /ellipsoid/ elp
|
|
|
|
type ellipsoid
|
|
sequence
|
|
real (8) r_a
|
|
real (8) r_e2
|
|
end type ellipsoid
|
|
type (ellipsoid) elp
|
|
|
|
real*8 r_v(3) !geocentric vector (meters)
|
|
real*8 r_llh(3) !latitude (deg -90 to 90),longitude (deg -180 to 180),height
|
|
|
|
c OUTPUT VARIABLES: see input
|
|
|
|
c LOCAL VARIABLES:
|
|
real*8 pi,r_dtor,r_re,r_q2,r_q3,r_b,r_q
|
|
real*8 r_p,r_tant,r_theta,r_a,r_e2
|
|
|
|
c DATA STATEMENTS:
|
|
data pi /3.141592653589793238d0/
|
|
data r_dtor /1.74532925199d-2/
|
|
|
|
C FUNCTION STATEMENTS:
|
|
|
|
c PROCESSING STEPS:
|
|
|
|
r_a = elp%r_a
|
|
r_e2 = elp%r_e2
|
|
|
|
if(i_type .eq. 1)then !convert lat,lon to vector
|
|
|
|
r_re = r_a/sqrt(1.d0 - r_e2*sin(r_llh(1))**2)
|
|
|
|
r_v(1) = (r_re + r_llh(3))*cos(r_llh(1))*cos(r_llh(2))
|
|
r_v(2) = (r_re + r_llh(3))*cos(r_llh(1))*sin(r_llh(2))
|
|
r_v(3) = (r_re*(1.d0-r_e2) + r_llh(3))*sin(r_llh(1))
|
|
|
|
elseif(i_type .eq. 2)then !convert vector to lat,lon
|
|
|
|
r_q2 = 1.d0/(1.d0 - r_e2)
|
|
r_q = sqrt(r_q2)
|
|
r_q3 = r_q2 - 1.d0
|
|
r_b = r_a*sqrt(1.d0 - r_e2)
|
|
|
|
r_llh(2) = atan2(r_v(2),r_v(1))
|
|
|
|
r_p = sqrt(r_v(1)**2 + r_v(2)**2)
|
|
r_tant = (r_v(3)/r_p)*r_q
|
|
r_theta = atan(r_tant)
|
|
r_tant = (r_v(3) + r_q3*r_b*sin(r_theta)**3)/
|
|
+ (r_p - r_e2*r_a*cos(r_theta)**3)
|
|
r_llh(1) = atan(r_tant)
|
|
r_re = r_a/sqrt(1.d0 - r_e2*sin(r_llh(1))**2)
|
|
r_llh(3) = r_p/cos(r_llh(1)) - r_re
|
|
|
|
endif
|
|
|
|
end
|
|
|