Thesis supervisor: Bence Takács
Location of studies (in Hungarian): BME Általános és Felsőgeodézia Tanszék Abbreviation of location of studies: EOAF
Description of the research topic:
The primary job of land surveying is to determine the position of natural and artificial features on the surface of the Earth in order to develop large-scale maps. For positioning and mapping, a reference-system is required, which must be either a global or a local system. While the global system is basically a geographic one based upon an ellipsoid of revolution, the local one is a two-dimensional system defined in the plane of the map. The map projection is the science to describe the mathematical connection between geographic and planar coordinates.
Majority of the countries in the world use their own national map projection system which defines the coordinate system of the national mapping systems, like the cadastral maps, at the same time. National mapping systems were introduced typically in the middle of the 20th century or even before; thus, its reference system, as well as its ellipsoid of revolution, are local. These local ellipsoids were localized in a way to minimize the differences between the physical shape of the Earth and the surface of the ellipsoid on the area of the certain country.
Thanks to GPS systems, positioning in a global system is quite common at the present time. However, there is a considerable demand for the transformation between the global system and the local (national) one, which can be achieved typically using approximate models and with limited accuracy. This kind of transformation uses common points; the position of these points is known both in the global and in the local (national) system.
The issues of transformation can be eliminated by introducing a global reference system instead of the local (national) one. This case, the transformation becomes mathematically exact since the same reference system, as well as the same ellipsoid of revolution, is used in both systems. On the other hand, it might have serious consequences; thus, a new national map projection system needs to be introduced. In addition, all the national mapping systems, like the land registry maps, need to be converted into the new map projection. Only a limited number of wealthy countries in the world have had this opportunity so far.
PhD student is supposed to plan a new map projection of a global ellipsoid of revolution to a specific country. In order to choose the most appropriate type of map projection and to optimize its parametrization, several factors need to be taken into consideration. One of the essential requirements is to minimize scale factors. In order to develop an adequate transformation model between the current and the planned systems, GNSS network with enhanced accuracy needs to be measured and processed. Support from the country is essential to complete the jobs in this research; therefore, the application must include a support letter from the relevant organization of the specific country.
The applicant is supposed to have studied Map projection, Geodetic networks, Adjustment calculations, Geodesy, Satellite positioning and Numerical methods during their former studies.
Number of students who can be accepted: 1
Deadline for application: 2024-05-31
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
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