Ellipsoid vs. Orthometric Elevations; Why is my GPS reporting an elevation 60 feet too low?

Mark Silver — public instruction filed under Geodesy & Datums. “Ellipsoid vs. Orthometric Elevations; Why is my GPS reporting an elevation 60 feet too low?.” Watch the module, then pass the topic quiz to post CE credit. The quiz checks the professional subject, not a transcript of the video.