Metres above the Adriatic
Metres above the Adriatic (Italian: Metri sopra l'Adriatico, German: Meter über Adria, Serbo-Croatian: Metara iznad Jadrana) is the vertical datum used in Austria, in the former Yugoslavian states of Slovenia, Croatia, Bosnia-Hercegovina, Serbia, Montenegro, North Macedonia, as well as in Albania to measure elevation, referring to the average water level of the Adriatic Sea at the Sartorio mole in the Port of Trieste.
Gauge[edit]
The gauging station in the Port of Trieste was established in 1875 by the local observatory run by the military geographical institute of the Austro-Hungarian Army. The average water surface elevation at Molo Sartorio became the datum valid for the whole Austro-Hungarian monarchy. Whilst the former Yugoslavian states still use it, the Eastern Bloc successor states of Austria-Hungary like Hungary and Czechoslovakia after World War II switched to the Kronstadt Gauge of the Baltic Sea, which is 0.6747 m (2.214 ft) higher.
Whilst for Austria the 1875 gauge is used as the datum, the states of former Yugoslavia use the 1900 gauge (Nadmorska visina, m/nv). In Albania (normal-orthometric height) they also refer to heights as 'metres above the Adriatic', but use a specific tide gauge in the port of Durrës.
Abbreviation[edit]
The individual countries using this datum abbreviate it in different ways depending on their local language, as follows:
- Austria: m ü. Adria, m.ü.A. or müA, colloquially known as Seehöhe or Adriahöhe
- Hungary: mAf from méter Adria felett
- Former Yugoslavian states: m. i. J. from Metara iznad Jadrana
'Metres above the Adriatic' may be abbreviated in English to m AA
Height differences between Austria and neighbouring countries[edit]
In Austria orthometric height is used, while its neighbours use other height systems, which leads to differences. On the state borders these differences are:
- Germany: +25 to +34 cm, normal height according to the Normalhöhennull levelling system based on the Amsterdam Ordnance Datum
- Italy: −0.5 to −3.2 cm, orthometric height referring to Genoa Tide Gauge
- Switzerland and Liechtenstein: −1.6 to −7.5 cm, orthometric height – 'Metres above the Sea' (Meter über Meer) based on the elevation of the Pierres du Niton in Lake Geneva at 373.6 m (1,226 ft) above average Marseille Tide Gauge
- Slovakia: +57 cm, normal height based on Kronstadt Tide Gauge
- Slovenia: −8 to −12 cm, orthometric height – metres above the sea referring to Koper Tide Gauge[1]
- Czech Republic: +46 to +56.3 cm, normal height based on Kronstadt Tide Gauge, and
- Hungary: +49.6 to +60.6 cm, normal height – 'Height above Sea Level' (Hungarian: Tengerszint feletti magasság) based on the elevation of the Nadap benchmark at 173.1638 m (568.123 ft) above Kronstadt Tide Gauge.
(Differences: HAustria − Hneighbouring states)[2]
See also[edit]
- Metre
- Normalhöhennull (NHN) (equivalent in Germany)
- Metres above the Sea (Switzerland)
References[edit]
- ^ "S pomočjo mareografske postaje v Kopru do novega geodetskega izhodišča za Slovenijo" [With the Help of a Tide Gauge Station in Koper to A New Geodetic Origin Point for Slovenia] (in Slovenian). Slovenian Environment Agency. 23 November 2016.
- ^ Map with height differences by the Austrian federal office for metrology and surveying, Bundesamt für Eich- und Vermessungswesen
External links[edit]
- (in Italian) Trieste Institute of Marine Sciences
- (in German) Austrian Federal Office of Metrology and Surveying Archived 2013-05-07 at the Wayback Machine