MERIDIAN DISTANCE R.E.Deakin School of Mathematical & Geospatial Sciences, RMIT University, GPO Box 2476V, MELBOURNE, Australia email:
[email protected] March 2006 ABSTRACT These notes provide a detailed derivation of the equations for computing meridian distance on an ellipsoid of revolution given ellipsoid parameters and latitude. Computation of meridian distance is a requirement for geodetic calculations on the ellipsoid, in particular, computations to do with conversion of geodetic coordinates φλ, (latitude, longitude) to Universal Transverse Mercator (UTM) projection coordinates E,N (East,North) that are used in Australia for survey coordination. The "opposite" transformation, E,N to φλ, requires latitude given meridian distance and these note show how series equations for meridian distances are "reversed" to give series equations for latitude. The derivation of equations follow methods set out in Lehrbuch Der Geodäsie (Baeschlin, 1948), Handbuch der Vermessungskunde (Jordan/Eggert/Kneissl, 1958), Geometric Geodesy (Rapp, 1982) and Geodesy and Map Projections (Lauf, 1983) and some of the formula derived are used in the Geocentric Datum of Australia Technical Manual (ICSM, 2002) – an on-line reference manual available from Geoscience Australia. An understanding of the methods introduced in the following pages, in particular the solution of elliptic integrals by series expansion and reversion of a series, will give the student an insight into other geodetic calculations. MATLAB functions for computing (i) meridian distance given