The paper describes the problem of conversion of heights to the European Vertical Reference Frame 2007 for Poland (PL-EVRF2007-NH). The subject of the study is height data, and especially the detailed vertical reference network. The aim of the article is to present an alternative method of conversion to the one recommended by the Polish Head Office of Geodesy and Cartography. The proposed approach is characterised by a low implementation cost while maintaining the required accuracy.
The publication is illustrated by the case of Kętrzyn district (in the north-east part of Poland). The local reference network was converted from Kronstad’60 to PL-EVRF2007-NH in 2017.
The paper presents a least squares collocation - based alternative to Helmert’s transformation with Hausbrandt’s post – transformation correction. The least squares collocation is used as an exact predictor i.e. it honors the data, thus the problem of zero residuals on transformation control points is overcome and zero residuals are assured by the method applied. Despite the fact that the procedure is presented for Helmert’s transformation it may easily be copied to any other form of coordinate transformation. A numerical example is provided within the content of the paper.
In these paper are presented two ways of performing leveling through terrain obstacles. They use properties of the quasigeoid course with respect to the ellipsoid within a given area. The analysis of changes in quasigeoid to ellipsoid slope have been made on the basis of the national quasigeoid models, calculating the slope components ξ, η. This allows to present practical recommendations for location of intermediate benchmarks in the leveling methods through obstacles.