(documentationmeanSeaLevelEnglishLanguage "(meanSeaLevel ?place ?measure) means that the Mean Sea Level (MSL) at ?place is ?measure. ?measure is a distance representing the sea level at ?place measured against a benchmark (and averaged over a long time). MSL is measured by tide gauges for maritime purposes, while geodesists use the difference between the local sea surface and an ideal level ocean surface (the geoid).")