Area network

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Area network is a term used in earth and land surveying for a geoid or surveying network that is built up step by step by filling in a superordinate frame or by compressing measuring points similar to a grid.

In the earth measurement one uses this procedure v. a. for geoid determination :

  • on the one hand, if newer data should be inserted into an older regional geoid in order to increase its accuracy,
  • on the other hand, if a profile-like point sequence - as it comes from classic degree measurements or from modern GPS leveling - is to be condensed over a large area by measuring profiles running across it.

In the land surveying , the method was used in the early 20th century for large triangulations in order to keep the computational effort (without aids such as today's IT ) bearable. A well-known application is the Area method developed by William Bowie (1924) for the USA triangulation . The processing of the huge survey network (4,000,000 km²) took place in 26 large rectangles, between which the node-shaped and line-shaped connections ("traverses") had previously been calculated. Subsequently, the approx. 500 km large sub- networks were merged and later extended to all of North America ( North American network NAD ).

A second such major project was the Central European Network , which began around 1940 and was completed after the Second World War under the leadership of Helmut Wolf and officers of the US occupation forces. It formed the basis of the later European network (see also ED50 and ED79 ), which, however, was calculated using "seams" along the national borders so that the national survey data of the individual countries did not have to be left to each other in full.

Similar processes are still in use today when operations are to be processed that significantly exceed the available computing capacity.

In geographic information systems , the term area network is sometimes used for an area that is completely covered by partial areas without any redundancy .

See also

literature