In both cases, '''altitude''' is the height of the respective point above the surface of the [[Ellipsoid]] and '''longitude''' is the angle between the planes parallel to the earth axis and passing through the Greenwich Meridian respectively the point designated by the coordinates. | In both cases, '''altitude''' is the height of the respective point above the surface of the [[Ellipsoid]] and '''longitude''' is the angle between the planes parallel to the earth axis and passing through the Greenwich Meridian respectively the point designated by the coordinates. |