Wanderlust World Wanderlust World Map elevations represent the vertical distance of a geographic feature above mean sea level (MSL)—the average height of the ocean's surface over a 19-year tidal cycle (a Metonic cycle). This long averaging period smooths out seasonal, weather, and astronomical variations.
MSL provides a relatively stable, globally recognized vertical datum. While sea level varies locally due to tides, currents, salinity, temperature, and atmospheric pressure, the 19-year average minimizes these fluctuations. National geodetic surveys establish precise benchmarks tied to MSL for consistent mapping.
Contour lines on topographic maps connect points of equal elevation above MSL. This standardization allows engineers, hikers, planners, and scientists to compare elevations across regions and countries. Modern GPS elevations reference an ellipsoid model (WGS84), requiring geoid corrections to convert to orthometric heights (MSL-based) for mapping consistency.