Comparison of two-dimensional transformation methods: The case of Trabzon province

Coordinate transformations have gained interest in recently especially with the cadastral renewal works to perform transformation from ED50 datum to ITRF96 datum with geodetic precision by using GNSS in our country. Datum transformation is performed in two dimensions for ellipsoid heights in ED50 datum cannot be determined with geodetic precision. In this thesis, coordinates of 139 points in ED50 and ITRF96 datums have been used for datum transformation in Trabzon province. With these points, use of parameters that are derived from a single datum transformation within the borders of the Trabzon province is aimed. For this purpose, two-dimensional similarity, affine and collocated similarity transformations with 10 and 16 common points that are homogeneously distributed throughout the province have been analyzed. The analysis has indicated that the collocated similarity method with 16 common points has yielded the best results both at 123 test points and at the common points used in datum transformations previously performed in different districts of the province. With the selected method, the average of square mean of the corrections in x and y directions has been obtained as 16.2cm at 123 test points and 18.1cm at the common points selected in ten different districts.