An approximate definition of sea level is the datum WGS 84, an ellipsoid, whereas a more accurate definition is Earth Gravitational Model 2008 (EGM2008), using at least 2,159 spherical harmonics.
Almaɣna hin ikkan iddikud wan ejarew inta s datum WGS 84, ellipsoid, as ijja awen almaɣna wa oɣadan hullan inta s Earth Gravitational Model 2008 ( EGM2008) isaxdaman 2.159.spherical harmonics