Atmospheric effects in geodetic levelling

The knowledge of physical processes and changes in the atmosphere is essential when addressing the fundamental problem, i.e. the accuracy of geodetic measurements. In levelling operations, all these changes are explained as the effect of refraction, which systematically distorts the results of levelling. Different ways of addressing the effect of refraction are represented based on the modelling of the vertical temperature gradient as the quantity that has the most influence on the refraction phenomenon

Selected legal issues of land cadastral surveying in Lithuania

This study is limited to the selected problematic aspects of cadastral surveys of land plots. Special attention is paid to the problem of on-site marking of the land plot boundaries. Authors have found that it determine imperative and complicated legal regulations. Cases where the act of marking-demonstration of the land plot boundaries is declared faulty in judicial practice are discussed. The problems of establishing the land plot boundaries are considered. Theoretical analysis is based on judicial practice. The advanced judicial practice demonstrates that immovable object cadastral surveys cannot correct legal ownership relationships

Accuracy calibration of the bars of levelling meters

Precision levelling is one of the most common geodetic measuring operations. The most modern geodetic instruments are quite sophisticated digital instruments that are supplied by photoelectric sensor arrays and optical–electronic cameras that fix the height values of terrain according to the position of the levelling meter that is placed on it. The marks on the levelling meters are also modified and consist of coded strokes put on the meter’s surface in a specific order. The accuracy of the performance of all the measuring equipment depends mostly on the accuracy of the position of those strokes. This paper deals with an analysis of an accuracy calibration of levelling meters, its methods and means of evaluation.

Determination of geographic position of object by applying 3D polar observations

The geographic position of an object is determined by geodetic latitude, geodetic longitude, geodetic and normal height, and height of the object above the surface of the earth. To determine the geographic position of an object, a technologic scheme is recommended: by applying 3D polar observations, the 3D Cartesian coordinates of the object in the local horizontal coordinate system (for example, with an airport runway tied system) are determined; local horizontal 3D Cartesian coordinates are recomputed into the system of geocentric equatorial 3D Cartesian coordinates; the geodetic coordinates (geodetic latitude, geodetic longitude, and geodetic height) are computed from the geocentric equatorial 3D Cartesian coordinates; based on information about geodetic height and the digital geoid model, the normal height of the object is computed; and object height above the earth is computed from normal height and the digital terrain model. Algorithms for the realisation of this technologic scheme are presented. Santrauka Objekto geografine padetis apibūdinama geodezine platuma, geodezine ilguma, geodeziniu bei normaliniu aukščiais ir objekto aukščiu virš Žemes paviršiaus. Objekto geografinei padečiai nustatyti rekomenduojama tokia technologine schema: taikant erdvinius polinius matavimus, nustatomos objekto erdvines stačiakampes koordinates vietineje (pvz., oro uosto) horizontineje koordinačiu sistemoje; vietines horizontines erdvines stačiakampes koordinates perskaičiuojamos i geocentriniu ekvatoriniu erdviniu stačiakampiu koordinačiu sistema; pagal geocentrines ekvatorines erdvines stačiakampes koordinates apskaičiuojamos geodezines koordinates (geodezine platuma, geodezine ilguma ir geodezinis aukštis); žinant geodezini aukšti ir turint skaitmenini geoido modeli, skaičiuojamas objekto normalinis aukštis; turint normalini aukšti ir skaitmenini reljefo modeli, apskaičiuojamas objekto aukštis virš Žemes paviršiaus. Pateikiami algoritmai šiai technologinei schemai realizuoti. First Publish Online: 14 Oct 2010 Reikšminiai žodžiai: koordinačiu sistema, geodezinis aukštis, GPS, normalinis aukštis, erdviniai poliniai matavima

Feasibility of integrated transport network model in Lithuania

Availability of up-to-date and detailed spatial data on transport networks is very important for sustainable development. As Directive 2007/2/EC of 14 March 2007 establishing an Infrastructure for Spatial Information in the European Community (INSPIRE) targets transport networks data as one of the first priority data themes to be harmonized across Europe, the specification for transport network dataset has been developed and adopted as guidance document for all Member States. The specification provides a common model for road, rail, air, water and cable transport networks and related infrastructure. Integrated transport network database can be used for routing of vehicles, taking into account all limitations of the road network, for transport planning, emergency services. In order to achieve the benefits related to common use of up-to-date information and to interoperable data for these tasks, all transport network elements must be accurately mapped in a consistent logical network. Unfortunately, in Lithuania there is no single continuous and extensive spatial data set (geographic database) of transport networks. The authors analysed the possibilities of building joint INSPIRE databases from different transport datasets, and indicated the best data sources for road and railway transport, as well as actions of improvement have to be taken. The research and successful experiment has showed that the more extensive INSPIRE transport data model can be implemented using ArcGIS data model. This concept and the model will serve as an important prop for development of policy of national and transboundary spatial data integration in countries with similar situation. INSPIRE implementation guidelines are compatible with national interest and must be followed, but technical feasibility and cost-benefit considerations must be taken into account

Accuracy research on coded levelling staff using digital photos

The article introduces accuracy research on coded levelling staff using digital photos. The principles of photogrammetry can be used for comparing the views of the etalon and meter to be calibrated. The etalon view is saved in the PC memory and the view of the tested meter must be extracted from the digital camera. All measurements are performed on the PC screen using an analyzing gap covering both images. Accordingly, gauges to measure deviations between the lines of the coded scales can be evaluated. The article is aimed at conducting accuracy research on coded levelling staff using digital photos. The conclusions are presented. Article in Lithuanian Niveliacijos matuoklių kodinių skalių tikslumo tyrimai pagal jų skaitmenines nuotraukas Santrauka. Pristatomas kodinių niveliavimo matuoklių tikslumo tyrimas pagal jų skaitmenines nuotraukas. Niveliavimo matuoklių brūkšnių padėties tikslumas nustatomas lyginant atraminės ir tikrinamos matuoklių fotogrametrinius vaizdus arba atraminį matą pakeitus fotogrametriniu atraminės matuoklės vaizdu, užfiksuotu skaitmeniniu fotoaparatu ir perkeltu į kompiuterio atmintį. Šiuo atveju atraminės kodinės niveliavimo matuoklės skalės brūkšnių padėtis yra lyginama su kalibruojamos matuoklės brūkšnių padėtimi. Pagal tai galima įvertinti matuoklių kodinių brūkšnių tarpusavio nuokrypius. Tyrimo tikslas – atlikti kodinių niveliavimo matuoklių tikslumo tyrimą pagal jų skaitmenines nuotraukas. Reikšminiai žodžiai: kodinės niveliavimo matuoklės, kalibravimas, skaitmeninis fotoaparatas, pikseliai

Modelling of the horizontal strains and stresses of the Earth-crust according to the data of geodetic measurements

The study was carried out by applying the Hooke's physical law - to describe the relationship of the horizontal strains and geodynamic stresses of the Earth-crust. Experimental studies were carried out in the territory of the geodynamic polygon of the Ignalina Nuclear Power Plant. New data of geodynamic stress changes that are significantly related with the tectonic structure of the territory were obtained. After the analysis and generalization of results obtained, the change of tectonic stresses in the surroundings of the geodynamic ground of the Ignalina Nuclear Power Plant and its connections with tectonic structure were determined. The conclusion is drawn that Hooke 's law, by describing the relations between horizontal strains of the Earth-crust and geodynamic stresses, may be used practically and applied for estimating the regularities of the geodynamic stress change

Calibration of Coded Levelling Staffs

Digital levels are a precise instruments used for precise leveling. Operation of digital levels is based on the digital processing of video indications of a coded staff. Changes in leveling methodology and sources of specific errors occur using digital levels for precise levelling. The marks on the leveling meters also are modified and consist from the coded strokes put on the meter’s surface in specific order. The accuracy of performance of all the measuring equipment mostly depends on accuracy of position of those strokes. This paper deals with an analysis of an accuracy calibration of leveling meters

Modelling of the Horizontal Strains and Stresses of the Earth-Crust according to the Data of Geodetic Measurements : Modeliranje horizontalnih deformacij in napetosti zemeljske skorje po podatkih geodetskih meritev

The study was carried out by applying the Hooke’s physical law – to describe the relationship of the horizontal strains and geodynamic stresses of the Earth-crust. Experimental studies were carried out in the territory of the geodynamic polygon of the Ignalina Nuclear Power Plant. New data of geodynamic stress changes that are significantly related with the tectonic structure of the territory were obtained. After the analysis and generalization of results obtained, the change of tectonic stresses in the surroundings of the geodynamic ground of the Ignalina Nuclear Power Plant and its connections with tectonic structure were determined. The conclusion is drawn that Hooke’s law, by describing the relations between horizontal strains of the Earth-crust and geodynamic stresses, may be used practically and applied for estimating the regularities of the geodynamic stress change

Accuracy calibration of the bars of levelling meters

Precision levelling is one of the most common geodetic measuring operations. The most modern geodetic instruments are quite sophisticated digital instruments that are supplied by photoelectric sensor arrays and optical–electronic cameras that fix the height values of terrain according to the position of the levelling meter that is placed on it. The marks on the levelling meters are also modified and consist of coded strokes put on the meter’s surface in a specific order. The accuracy of the performance of all the measuring equipment depends mostly on the accuracy of the position of those strokes. This paper deals with an analysis of an accuracy calibration of levelling meters, its methods and means of evaluation.Lietuviška santrauka. Precizinis niveliavimas yra vienas iš plačiausiai taikomų geodezinio matavimo darbų. Niveliavimo prietaisai, kaip ir daugelis kitų geodezinių prietaisų, pastaruoju metu labai modernūs – skaitmeniniai, turintys fotoelektrinių elementų matricas ir optinę-elektroninę kamerą, fiksuojančią aukščio padėtį pagal matuojamame taške pastatytą matuoklę. Matuoklės žymės taip pat jau patobulintos ir susideda iš kodinių brūkšnių, tam tikra tvarka sužymėtų per visą matuoklės ilgį. Nuo šių brūkšnių padėties tikslumo labai priklauso viso niveliavimo komplekso darbo tikslumas. Šis straipsnis skirtas niveliavimo matuoklių tikslumo tikrinimo-kalibravimo būdų ir priemonių analizei