I have an ellipse of semi-axis major
x-axis and semi-axis minor
Having a point
C defined with its geodetic (not geocentric) latitude $\varphi_1$ on the ellipse surface then drawing a point
D along the normal line by height
h, so segment
CD = h.
Then I draw the tangent lines from
D to the ellipse, they touch the ellipse at tangent points
G, also defined by its geodetic latitude $\varphi_2$.
The normal line at point
G intersects the tangent line
(DE) at point
My question is, how to find the height
m of the segment
For a circle I would know how to calculate it but for an ellipse, it's complicated :(