Determining the Gps/levelling geoid undulations by interpolation methods for the region of Trabzon, Turkey

Finding the traditional measure of orthometric heights used in engineering applications is quite difficult and time consuming conversion easier for those who ellipsoid height of known height with GNSS measurements Although the process. But it is also necessary to know the value of the geoid undulation with certain accuracy for conversion. In this study, the Land Registry and Cadastre Trabzon IX. Regional Directorate of cadastral works covered east-west direction of 80 km, measured orthometric and ellipsoidal heights in the 600 C3 point values created in an area 30 km long north-south direction is used. All points ITRF96 (International Terrestrial Reference Frame) three-dimensional Cartesian coordinates based on datum, projection coordinates are known and defined in the Gauss Krüger projection system. Practice is divided into two basis points, and test points. The selection of the mainstay, has been looking at the x and y axis direction of the point spread. In this study, weighted average, polynomial surfaces and multiquadratic interpolation methods are used. Selected mainstay of known ellipsoidal and orthometric heights are aware of using computed geoid undulations of different interpolation methods with the calculated orthometric height for test points, comparisons between the interpolation method by calculating the difference from the known height known at this point is made. Various benchmarks related to the implementation of the results obtained through interpolation methods for different groups in the number of basis-test point is made.