Created
May 1, 2016 17:16
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function [lat, lon, h] = xyz2ell(X, Y, Z, a, e2) | |
% XYZ2ELL Converts cartesian coordinates to ellipsoidal coodinates. | |
% We can add some default values here, i.e. a and e2. | |
% Latitude and height convergence criteria | |
eps_lat = 1.e-12; | |
eps_height = 1.e-5; | |
% Initial values... | |
p = sqrt(X .* X + Y .* Y); | |
lat = atan2(Z, p .* (1 - e2)); | |
h = 0; | |
dh = 1; | |
dlat = 1; | |
% Iterate until convergence, the difference between lat(i) and lat(i - 1) <= eps, and so for the height. | |
while sum(dlat > eps_lat) | sum(dh > eps_height) | |
lat0 = lat; | |
h0 = h; | |
v = a ./ sqrt(1 - e2 .* sin(lat) .* sin(lat)); | |
h = p ./ cos(lat) - v; | |
lat = atan2(Z, p .* (1 - e2 .* v ./ (v + h))); | |
dlat = abs(lat-lat0); | |
dh = abs(h - h0); | |
end | |
lon = atan2(Y, X); | |
% For reference for atan2() uses refer to cens.ioc.ee/local/matlab/techdoc/ref/atan2.html |
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