First-order trigonometric network in the former Yugoslavia

Abstract

State surveys in a number of countries still use networks developed according to the principles that were applicable over 100 years ago or more. During that period, the rule was that the networks were developed in the classical geodetic datum, using the principle of relative positioning. Basic measured data were the angles and basis networks for scale definition, and measured data was not rectified to reflect the influence of physical parameters of the Earth (deflection of vertical). Given the types of measured values, reduction and positioning, these networks are called trigonometric and are divided into orders. The main network is 1st order and was used to develop networks of lower ranks-up to the point for details surveying. In the former Socialist Federal Republic of Yugoslavia trigonometric networks of the 1st order were developed in accordance with the recommendations of international organizations. We deliberately say "networks" because the 1st order trigonometric network of the former Yugoslavia was not developed as a single entity, but consisted of several parts. It is useful to know the history of the development and the accuracy of 1st order trigonometric networks because all surveys rely on this network, as the data obtained with new technology (GPS) is expected to fit into the existing system (Völgyesi in Transformation of Hungarian Unified National and Gauss-Krüger Projection System into WGS-84, Reports on Geodesy, 1997). The paper will present the historical facts relating to the development of 1st order trigonometric networks in the former Yugoslavia, without any analysis of the results of measurements and adjustment of individual parts of the network.

Triangle-based Horizontal Geodetic Datum Transformations in Bosnia and Herzegovina

“…The development of the triangulation network in Bosnia and Herzegovina spanned almost nine decades, and it was never adjusted as a one network. Instead, adjustment was done by blocks (Delčev et al, 2015) (refer to Figure 14). The accuracy of the trigonometric network in Bosnia and Herzegovina has never been established.…”

Predikcija Položajne Greške Tačaka Trigonometrijske Mreže Prvog Reda

“…After completely establishing this first order trigonometric network, the network was densed (through several phases) by inserting new trigonometric points which comprise lower level networks. This process was further repeated and until finally traverse networks and line networks were established and used for cadastral surveying of the country [12]. During establishment of the first order network, only geometrical quantities on the physical surface of the Earth were measured -angles and baselines.…”

“…Errors resulting from not taking into account the impact of Earth's gravitational field were present in coordinates of first order network points, and in all subsequent networks derived from this network. All these networks and cadastral data from first and other early country-level surveying campaigns are still in use today [12] [13]. Subsequent analysis and measurements were conducted in order to determine errors resulting from neglecting the influence of Earth's gravitational field.…”