MSL Mean Sea Level Originally from CUAHSI HIS ODM CV. See http://his.cuahsi.org/mastercvreg/edit_cv11.aspx?tbl=VerticalDatumCV. ODM2 Elevation Datum Controlled Vocabulary ODM2 Working Group A vocabulary for describing vertical datums. Vertical datums are used in ODM2 to specify the origin for elevations assocated with SamplingFeatures.