Amsterdam Ordnance Datum or Normaal Amsterdams Peil ( NAP ) is a vertical datum in use in large parts of Western Europe . Originally created for use in the Netherlands , its height was used by Prussia in 1879 for defining Normalnull , and in 1955 by other European countries. In the 1990s, it was used as the reference level for the United European leveling Network (UELN) which in turn led to the European Vertical Reference System (EVRS).
20-533: The Vaalserberg ( Dutch pronunciation: [ˈvaːlsərˌbɛr(ə)x] ) is a hill with a height of 322.4 metres (1,058 ft) above NAP and is the highest point in the European part of the Netherlands . The Vaalserberg is located in the province of Limburg , at the south-easternmost edge of the country, near the town of Vaals (after which it is named). The Vaalserberg was the highest point anywhere in
40-591: A 50 metres (160 ft) tower on the Belgian side ( Dutch : Boudewijntoren ; French : Tour Baudouin ; German : Balduin-Turm ), opened in 1994 to replace the previous 33 metres (108 ft) tower, built in 1970. It offers a grand panorama of the surrounding landscape. 140 metres (460 ft) south of the point, a railway crosses the German-Belgian border in the Gemmenicher Tunnel . It
60-545: A new port , IJmuiden ("IJ's mouth") was built at its west end. The east end of the IJ polders near Amsterdam was given over to industry, and a large new seaport area was constructed. The Buiten-IJ hosted the mixed dinghy sailing events for the 1928 Summer Olympics in neighboring Amsterdam. It also hosted two events for the 1920 Summer Olympics in Antwerp . The nautical event SAIL Amsterdam takes place on and around
80-476: A way came up with the idea after he expanded the sea dike after a flood in Amsterdam in 1675. Of course a dike should be storm-resistant to protect a city against flooding, and in this case a margin of "9 feet and 5 inches" (2.67 m - margin is defined in Amsterdam feet) was deemed enough to cope with rising water. So he measured the water level of the adjacent sea arm, Het IJ , and compared it with
100-571: Is a body of water , formerly a bay , in the Dutch province of North Holland . It is known for being Amsterdam 's waterfront. The name IJ is derived from the West Frisian word ie , alternatively spelled ije , meaning 'water' and cognate with the English word ea . The name consists of the digraph ij which is capitalized as IJ . Today, the IJ is divided into two parts: The IJ
120-657: Is connected to the North Sea to the west and the IJmeer to the east by a set of locks . There are several theories about the origins of the IJ. Perhaps it began as a stream, following a breakthrough in the dunes of Castricum . More likely, the IJ is a remnant of a northern arm of the Rhine delta . Finally, the IJ could also come from the lake Almere or Flevo . During the Roman period the IJ connected on one side with lake Flevo and
140-524: Is not the same as the former eastern border of Moresnet with Prussia but is a little more to the east. Therefore, five different borders came together at this point but never more than four at one time, except possibly between 1917 and 1920, when the border situation was unclear and disputed. The border intersection has made the Vaalserberg a well-known tourist attraction in the Netherlands, with
160-413: Is the 35 metres (115 ft) Wilhelminatoren observation tower, with a restaurant and forest trails. The present tower officially opened on 7 October 2011 and features a lift and a glass floor. The first tower at the site was built in 1905 during the reign of its namesake, Queen Wilhelmina of the Netherlands , and was demolished in 1945. The second 20 metres (66 ft) tower opened on 11 August 1951 and
180-575: Is the freight-only railway between Tongeren and Aachen . The road leading up to this point on the Dutch side is called the Viergrenzenweg ("four borders way"), probably because of the former territory of Neutral Moresnet . The names of the roads in Belgium ( Route des Trois Bornes ) and Germany ( Dreiländerweg ) refer to the present three bordering countries. Along the road on the Dutch side
200-532: The Dam square in Amsterdam. The brass benchmark in the Amsterdam Stopera (combined city hall and opera house), which is a tourist attraction, is no longer used as a reference point. 52°22′23″N 4°53′34″E / 52.37306°N 4.89278°E / 52.37306; 4.89278 IJ (Amsterdam) The IJ ( Dutch: [ɛi] ; sometimes shown on old maps as Y or Ye )
220-646: The Vecht (Utrecht) and the other with the North Sea. Connection with the North Sea has subsequently disappeared, while the IJ in the Middle Ages has expanded. This is due to the emergence of the Zuiderzee , itself a bay of the North Sea resulting from a number of storms. At the end of the Middle Ages , the IJ was a long and narrow brackish bay that connected to the Zuiderzee and stretched from Amsterdam in
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#1732787375738240-430: The Belgian side, the tripoint borders the region of Wallonia , including both the regular French-speaking area and the smaller German-speaking area . The German side falls within the city limits of Aachen in the state of North Rhine-Westphalia . Between 1830 and 1919, the summit was a quadripoint , also bordering Neutral Moresnet , which is now part of Belgium's German-speaking area. The current Belgian-German border
260-741: The Netherlands until the Caribbean island of Saba , with its 887 m (2,910 ft) high volcano , was incorporated into the country as a "special municipality" in 2010. The Vaalserberg is also the location of the tripoint between Germany , Belgium and the Netherlands and so its summit is called the Drielandenpunt ("three country point") in Dutch, Dreiländereck ("three country corner") in German and Trois Frontières ("three borders") or Trois Bornes ("three border stones") in French. On
280-401: The datum for first-order levelling. The relatively constant water level in the canals of Amsterdam, called Amsterdams Peil ("Amsterdam level", AP), was equal to the level at summer flood at sea in the sea-inlet, which changes throughout the year. AP was carried over to other areas in the Netherlands in 1860, to replace locally used levels. In this operation, an error was introduced which
300-556: The east to Velsen in the west. At its west end, only the natural dune ridge across the Dutch North Sea coast prevented the IJ, which grew ever larger through the centuries, from directly connecting to the North Sea and so making the North Holland peninsula nearly an island. By the seventeenth century, however, access to the IJ became difficult due to sand bars across its mouth, and ships becoming bigger, and it
320-586: The largest part of the IJ followed suit between 1865 and 1876, with only a small lake remaining at Amsterdam that was closed off from the Zuiderzee by the Oranje locks . At the same time, the North Sea Canal was constructed in the former IJ basin to provide Amsterdam with access to the sea again and revive its ailing port . It cut through the isthmus to connect to the North Sea near the town of Velsen;
340-513: The water level in the canals within the city itself. He found that the water level at an average summer flood in the sea arm (when the water level reaches its maximum, not counting storms) was about the same as the level on the other side of the sea-dike, plus the margin of 9 feet and 5 inches. In 1850, the datum was used at several places in Belgium , and in 1874 the German government adopted
360-489: Was corrected (normalised) between 1885 and 1894, resulting in the Normaal Amsterdams Peil . Originally the zero level of NAP was the average summer flood water level in the IJ just north of the centre of Amsterdam (which was at the time, in 1684, the main shipping area, then still connected with the open sea). Currently it is physically realised by a brass benchmark on a 22-metre (72 ft) pile below
380-682: Was demolished over the winter of 2010–2011 because of its poor condition and high maintenance requirements. The Vaalserberg is often used in the Amstel Gold Race and is climbed halfway through the race. The climb is named in the roadbook of the Gold Race as Drielandenpunt and is followed by the Gemmenich climb. 'Tim Travel': Holland's highest mountain (& the strange story of Neutral-Moresnet) ( YouTube ) Amsterdam Ordnance Datum Mayor Johannes Hudde of Amsterdam in
400-556: Was nearly impossible for seafaring vessels to reach the city of Amsterdam. At the same time, the bay gnawed away at the surrounding farmlands , almost connecting with the Haarlemmermeer (Lake Haarlem) and seriously threatening the cities of Haarlem and Amsterdam. Plans were put forth to reclaim both the Haarlemmermeer and the IJ and turn them into polders . The Haarlemmermeer was first, falling dry in 1852, and
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