Complex sentence: Since latitude is defined with respect to an ellipsoid the position of a given feature is different on each ellipsoid: it is meaningless to specify the latitude and longitude of a geographical feature without specifying the ellipsoid used.
Split into simpler sentences: Since latitude is defined with respect to an ellipsoid the position of a given feature is different on each ellipsoid. It is meaningless to specify the latitude and longitude of a geographical feature without specifying the ellipsoid used.