  The manuscript establishes a series expansion of the core integral that
relates changes in longitude and latitude along the geodetic line in oblate
elliptical coordinates, and of a companion integral which is the path length
along this line as a function of latitude. The expansion is a power series in
the scaled (constant) altitude of the trajectory over the surface of the
ellipsoid. Each term of this series is reduced to sums over inverse
trigonometric functions, square roots and Elliptic Integrals. The aim is to
avoid purely numerical means of integration.
