Normaal Amsterdams Peil

Normaal Amsterdams Peil (NAP) or Amsterdam Ordnance Datum is a vertical datum in use in large parts of Western Europe. Originally created for use in The Netherlands, it was adopted by Prussia

Prussia

Prussia was a historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries this state had substantial influence on German and European history...

 in 1879 under the name Normalnull, and in 1955 by other European countries.

Originally the zero level of NAP was the average summer flood water level (not mean sea level

Sea level

Mean sea level is the average height of the ocean's surface ; used as a standard in reckoning land elevation.- Measurement :...

) in the IJ

IJ (bay)

The IJ is a river, formerly a bay, in the Dutch province of North Holland. It is known for being Amsterdam's waterfront. The name derives from the generic Germanic term for "water" and is similar to other Aa/Ee names for bodies of water...

 in the centre of Amsterdam, then still connected with the open sea, in 1684.

Normaal Amsterdams Peil (NAP) or Amsterdam Ordnance Datum is a vertical datum in use in large parts of Western Europe. Originally created for use in The Netherlands, it was adopted by Prussia

Prussia

Prussia was a historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries this state had substantial influence on German and European history...

 in 1879 under the name Normalnull, and in 1955 by other European countries.

Originally the zero level of NAP was the average summer flood water level (not mean sea level

Sea level

Mean sea level is the average height of the ocean's surface ; used as a standard in reckoning land elevation.- Measurement :...

) in the IJ

IJ (bay)

The IJ is a river, formerly a bay, in the Dutch province of North Holland. It is known for being Amsterdam's waterfront. The name derives from the generic Germanic term for "water" and is similar to other Aa/Ee names for bodies of water...

 in the centre of Amsterdam, then still connected with the open sea, in 1684. Currently it is physically realized by a bench mark in brass in the centre of Amsterdam, which is a popular tourist attraction.

Currently NAP is close to mean sea level at the Dutch coast.

External links

• History of NAP van der Weele, 1971, Dutch Royal Society for Sciences, Governmental Commission for Geodesy
• http://home.tiscali.nl/~wr2777/NAP-niveau.htm (In Dutch
  Dutch language
  Dutch is a West Germanic language spoken by over 22 million people as a native language, and over 5 million people as a second language.
  "1% of the EU population claims to speak Dutch well enough in order to have a conversation." Outside the European Union the number of second language...
  
  )