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