Introduction - Description directory of the Hungarian Geodetic Reference

1 Introduction

For modernization of the Hungarian mapping bases the EOV projection system and the HD-72 Datum and reference system have been introduced in 1972 by the civilian National Mapping Agency.

As reference surface common for the EOV projection and the HD-72 Datum the Geodetic Reference System recommended by the International Union of Geodesy and Geophysics in 1967 (the IUGG GRS 1967) has been selected. The altitude system is defined above the Baltic sea.

The Hungarian reference system has been defined using the Hungarian Astrogeodetic Network adjusted on Krassovskij ellipsoid and transformed onto the IUGG GRS 1967 ellipsoid. In this procedure the Hungarian Datum 1972 (HD-72) has been defined as being located and oriented relatively at terrestrial Geodetic Datum point Szőlőhegy. The azimuth from Szőlőhegy to Erdőhegy is fixed.

The EOV system (Egységes Országos Vetületi rendszer, Uniform National Projection system) is a conformal cylindrical projection in transversal position used uniformly for the Hungarian civilian base maps.

Any point of the earth surface in Hungary is represented on the map by the EOV plane coordinates. For this - after reductions to the direct surface measurements - the projecting procedure is performed in two steps: firstly, from the ellipsoid to the best fitting Gauss-sphere and, secondly, from this sphere to the plane of EOV.

The HD-72-equivalent three-dimensional rectangular coordinates (XYZ) of a point can be obtained from the HD-72 IUGG GRS 1967 ellipsoidal coordinates of the point, using the IUGG GRS 1967 ellipsoid parameters and by help of known formulas.

In general case and for international use the transformation from EOV (and the respective heights) to any other projection system can be performed as it follows:

from EOV to HD-72 (see chapter 4),
from HD-72 to one of Global reference frames (to WGS-72 or to EUREF-89 [as a realization of WGS-84], see chapter 5),
from global reference frame to the Datum of interest,
from Datum of interest to the projection system in goal.

Analogous procedure can be set up for a backward transformation.
Below, description directory of the projection and reference systems, the basic data and transformation parameters are given.

Source of information:
Joó, I., 1974; MÉM OFTH, 1975; Varga, J., 1988; Mihály, Sz., 1991; Remetey, F.G.-Mihály, Sz., 1992; Personal communications; (see Chapter 8).

Back to the Description directory of the Hungarian Geodetic Reference

Jump to the Homepage of Department of Cartography and Geoinformatics, Eötvös University, Budapest