Perbezaan antara semakan "Datum Tegak Amerika Utara 1988"

tiada ringkasan suntingan
'''Datum Tegak Amerika Utara 1988''' (NAVD 88) is the vertical controlialah [[Datum (geodesy)|datum]] establishedkawalan fortegak verticalyang controldiasaskan untuk [[surveyingpensurveian]] inkawalan thetegai di [[UnitedAmerika States|UnitedSyarikat, Statesberdasarkan ofPelarasan America]]Umum basedDatum upon the General Adjustment of the North American DatumAmerika ofUtara 1988.
 
The NAVD 88 wasdiasaskan established inpada [[1991]] bymenerusi thepelarasan [[kekangan]] minimum-constraint adjustmentterhadap ofcerapan-cerapan pengarasan [[geodeticgeodesi]] leveling observations indi [[CanadaKanada]], the [[UnitedAmerika StatesSyarikat]], anddan [[Mexico]]. It held fixed the height of the primary tidal bench mark, referenced to the International Great Lakes Datum of 1985 local mean sea level height value, at [[Rimouski]], [[Quebec]], [[Canada]]. Additional tidal bench mark elevations were not used due to the demonstrated variations in sea surface topography, i.e., the fact that mean sea level is not the same equipotential surface at all tidal bench marks.
 
NAVD 88 menggantikan [[Datum Tegak Geodesi Negara 1929]] ([[NGVD 29]]) yang dahulunya dikenali sebagai [[Datum Aras Laut 1929]].