| Tittel: | Om høyde og ny vertikal referanseramme NN2000 : About height and the new vertical reference frame NN2000 | | Ansvar: | Inge Revhaug | | Forfatter: | Revhaug, Inge  | | Materialtype: | Artikkel - elektronisk | | Signatur: | Kart og plan | | Utgitt: | Bergen : Universitetsforlaget, 2019 | | Omfang: | S.54-64 | | ISBN/ISSN: | 0447-3278 | | Serie: | Kart og plan ; 1/2019 | | Note: | Har engelsk sammendrag | | Innhold: | In 2018, the New Norwegian reference frame for height NN2000 is introduced in the whole country. Following NN1954, which was a national frame, NN2000 is connected to the European Vertical Reference System EVRS 2007 by the Baltic Ring. The Baltic Ring is a separate Nordic adjustment and differs slightly from the final EVRS 2007 result. For EVRS 2007 and NN2000, the heights are computed as they were in the beginning of the year 2000. While NN1954 ignored isostatic land uplift, for NN2000 under the Nordic Geodetic Commission, models to correct this have been developed and implemented in the software. Gravitational forces due to the moon and sun create earth tides. The average of the tides is named permanent tide. In EVRS 2007 and NN2000 the zero tidal system is applied, meaning that one removes the direct effect of the attraction from the sun and the moon, but retains the indirect effect caused by the deformed crust. | | Del av verk: | Kart og plan 1/2019 |
|
|