Status and evaluation of accuracy of the polygonometric network of Kaunas city and region

Abstract

The article analyses the aspects of the development of the geodetic basis network (polygonometric) of Kaunas city and region. The alteration of network accuracy after its coordinates had been transformed to the State coordinate system LKS – 94 and the relation of measured values are assessed. The polygonometric network of Kaunas city had been finished in 1975. Later, as the geodetic base of Kaunas city had been densified, the coordinates of this network had been transformed to the State coordinate system LKS – 94. 1374 ground points and 537 wall points have been transformed. The accuracy of the Kaunas city geodetic basis after the transformation of the coordinates is evaluated according to the linear values, by examining the movement lengths of the geodetic basis and the misalignment of such lengths after the network transformation. During the transformation in Kaunas region, the geodetic basis network of 28 villages has been transformed separately. The precision of the network following the transformation is evaluated according to the average square error of local network positioning. After the transformation to the LKS – 94 system, the precision of almost 36% network points has been modified. During the determination of the interdependent links in the local coordinates system, the average square error of the measured network has little impact on the precision of performed transformation. The correlation between the average square error in the local network and the network, transformed to the LKS – 94 system is not crucial. The linear noncomformity after the coordinates’ transformation is proportionate to the line length, measured in the local coordinates system.