Surveying and mapping 
| Surveying and Mapping |
|
|
|
| Written by Bjørn Geirr Harsson | |
| Tuesday, 24 July 2007 | |
|
Surveying is the technique and science of very precise three-dimensional positioning of points. These points are used when making maps. Another important usage is the determination of boundaries and various engineering purposes. Surveying has been a very essential part in developing the human environment since the beginning of recorded history.  A rubbing taken from a 4,000-year-old stone tablet in Sian, the ancient capital of China, represents one of the oldest extant maps. Made in 1935 by Prof. W. B. Pettus of the College of Chinese Studies at Peking and given to the Library by George B. Cressey, Professor of Geography, Syracuse University, the map was apparently prepared for pedagogical purposes. It delineates the provinces of China which paid tribute to Emperor Yu, the founder in 2205 b.c. of the first legendary dynasty. (Vault Map Collection) In many European countries national surveying and mapping agencies were established by military organisations in the 1700's. In scientific circles from that time and up today the big task was to determine the size and the shape of the Earth. The Russian astronomer and geodesist Friedrich Georg Wilhelm Struve carried out a major geodetic survey during the first half of the Nineteenth century in order to determine the flattening of the Earth at the Poles. Surveying and mapping demands for increased accuracies had made it important to determine the shape and the size of the Earth with greater precision. Geodetic measurements were made in the form of a chain of triangulation along the meridian stretching from Ismail on the Black Sea in the South to Fuglenes in Hammerfest in the North. A meridian is an imaginary line on the Earth’s surface running from Pole to Pole, and geodetic surveying measurements along a meridian – known as Geodetic Arc Measurements – can be used to calculate the Earth’s accurate shape and size. Struve’s work took place between 1816 and 1855. Today, however, Struve’s methods have been replaced by the use of satellite technology. The Struve Geodetic Arc was added to the UNESCO World Heritage List in 2005, and so letting geodesy becoming the first technical and scientific object to be accorded this prestigious status. The ten countries through which Struve’s Arc had passed, joined together to have 34 of the original triangulation stations entered into the UNESCO World Heritage List. In its decision statement, UNESCO judged that The Struve Geodetic Arc represents the first accurate measuring of a long segment of a meridian, helping in the establishment of the exact size and shape of the world exhibits an important step in the development of earth sciences. It is also an extraordinary example for interchange of human values in the form of scientific collaboration among scientists from different countries. It is at the same time an example for collaboration between monarchs of different powers, for a scientific cause. Short after the Struve had published his two books about the meridian arc measurement from the Black Sea to Hammerfest Norway, the precursor of International Association of Geodesy (IAG) was formed in Prussia with the same idea to measure another European geodetic arc. Later IAG became a part of The International Union of Geodesy and Geophysics (IUGG), which in this way can be said to have emerged from Struve’s original work, and is fully active to this day as a Union within the International Council for Science (ICSU) under the general umbrella of the United Nations. |
|
| Last Updated ( Sunday, 24 August 2008 ) |
| < Prev | Next > |
|---|
