📌 Ellipsoid vs Geoid — Easy Explanation for Surveyors Understanding the difference between Ellipsoid and Geoid is very important in land surveying, GPS work, and elevation calculations. 🔹 Ellipsoid A smooth, mathematical model of the Earth used in: GPS calculations Mapping & coordinate systems Lat, Lon & Ellipsoidal Height (h) Example: WGS84 🔹 Geoid A natural gravity-based shape of the Earth that represents Mean Sea Level (MSL). Used for: Orthometric Height (H) Elevations above sea level Exam