A unified and continuous national vertical network is the back-bone for geodesy, cartography, civil engineering and global positioning. International institutions are working to reach homogenous and unified vertical datum all around the globe. Levelling evaluation on the border between Latvia and Lithuania is of particular interest. Connection between vertical networks is made in three places, so connecting lines construct the two first order levelling loops. A joined loop adjustment produces a good basis for analysis and evaluation of height connection between Latvia and Lithuania not only as neighbouring countries but also as parties to the EVRS.

The horizontal deformation analysis of high-rise buildings, quite often is complicated because buildings like chimneys, towers and etc, have complex and asymmetric shapes, consequently there is not always the possibility to apply the method of single points motion analysis. Furthermore, the horizontal deformation analysis is complicated using standard measurement methods like measurements with electronic total stations or optical theodolites. In such case the terrestrial laser scanner could be superior to traditional measurements. However, the terrestrial laser scanner still not widely used to survey building horizontal deformations using high precision measurements. The main aim of this work is to determine the suitability to measure deflections of buildings from the vertical using terrestrial laser scanners and to investigate point cloud data processing. Measurements of horizontal deformation were carried out using the over ground laser scanner and electronic total station. Horizontal deformations of chimneys of thermal power plants were investigated using corresponding methods. Deformation indicators and evaluated measurement accuracies between different methods were compared. Data analysis of terrestrial laser scanning is more complex, time consuming and requires sophisticated hardware resources in comparison with the traditional methods, however results are much more detailed and informative.

Activities of Lithuanian National Geodetic Vertical Reference Network (NGVRN) establishment are going on since 1998. The goal of NGVRN establishment is a creation of new Lithuanian height reference suitable for present period practical and scientific needs. The Lithuanian Geodetic Vertical First Order Network consists of five polygons. Perimeter of the network is ca. 1900 km. Its development was finished in 2006. Connections of the first order vertical network with the vertical networks of neighbouring countries were established. All this creates good preconditions for determination of relations between height systems and for introduction of a new Lithuanian geodetic vertical (height) system. But this network is not dense enough to transfer the geodetic vertical system to the all territory of Lithuania and to improve the geoid model. It is necessary to dense available First Order Geodetic Vertical Network by developing the Second Order Geodetic Vertical Network. The territory of Lithuania is divided into five regions. Borders of the regions are First Order Network levelling lines and lines connecting Lithuanian national Vertical Network to the corresponding networks of the neighbouring countries. The regions are called: South, East, North, West and Centre. The design of the Second Order Geodetic Vertical Network is presented. The necessary density, accuracy of the geopotential numbers and ellipsoidal heights are discussed. Some results of the geodetic measurements are presented too.

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