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The article presents the renovation and upgrading of the urban leveling network of the municipality of Ljubljana. The old measurements in the of the municipality of Ljubljana area, the renovation project and the form of the new leveling network as well as the leveling measurement are presented. The pre-processing of the data is described. Based on the analysis of the stability of the 1st order benchmarks of the leveling network of Slovenia, the predetermined benchmarks for the adjustment of the leveling network were selected. The precision is analyzed based on the deviations of the both sides measured height differences, the deviations when closing the leveling loops and the corrections of the measured height differences after adjustment.

In this work, we analyzed the quality of height transformation between the old height system SVS2000 (vertical datum Trieste) and the new height system SVS2010 (vertical datum Koper). Based on the height differences of the benchmarks between the old and the new height systems stabilised in the area of eastern Slovenia, we determined the height transformation surface for two areas of different sizes. For both areas we analyzed the influence of different interpolation methods and the influence of using height differences of benchmarks of different orders of the levelling net. We found that the quality of height transformation is satisfactory for most surveying services. We have also analyzed the quality of the height transformation based on the average height difference of the benchmarks by using the SiVis software, which is intended for the transformation of ellipsoidal heights obtained by GNSS measurements, between the old and the new height systems.

This paper describes the quality determination of heights above mean sea level using RTK GNSS-levelling and new height reference surface SLO_VRP2016/Koper on the city area of Ljubljana. At 57 chosen benchmarks, quasigeoid heights were determined using ellipsoidal heights, determined with RTK GNNS-levelling technique and heights above mean sea level in the new height system SVS2010. The measured quasigeoid heights were compared with values interpolated from the new height reference surface SLO_VRP2016/Koper.

Recently, a new national height reference system was implemented: the Slovenian Height System 2010 (SVS2010). This new system replaced the Slovenian Height System 2000 (SVS2000). It is a new realisation of a national height system, which is based on new levelling and gravity surveys and recent tide gauge data. Its implementation changes the height datum (from Trieste to Koper) as well as the type of heights (from normal-orthometric to normal). Consequently, differences between the old and new height reference systems from 1.4 cm to 30.8 cm were detected. Unfortunately, there is no simple transformation between the two height reference systems. The surveyor must choose an appropriate method of local transformation or recalculation based on the given data and the required accuracy. To provide all necessary information for the users, the Surveying and Mapping Authority of the Republic of Slovenia has, in cooperation with the Faculty of Civil and Geodetic Engineering at the University of Ljubljana, prepared a new Technical instruction for the use of the new national height system. Online software called SiVis is also available for converting GNSS-based heights into both height reference systems (SVS2000 and SVS2010). Due to some problems with the (old) AMG2000/Trst geoid model near the national boundary, this model was extrapolated to a buffer covering parts of neighbouring countries. EPSG codes for both national height reference systems of Slovenia were also created.

In December 2018, a new national height system called the ‘Slovenian Height System 2010’ was introduced (denoted as ‘SVS2010’). It is based on a new levelling network of the first order, which has been measured over the previous decade. For geopotential number computation with simultaneous levelling measurements, gravimetric measurements were carried out on the benchmarks of the first order levelling network. Based on geopotential numbers, normal heights were computed, as they were chosen as the new official type of heights. A new height datum has also been introduced, determined from 18.6 years of sea level observations on the tide gauge station in Koper, Slovenia with the mean epoch 10. 10. 2010. The new height reference surface (quasi-geoid), named ‘SLO_VRP2016/Koper’ was determined. All levelling lines of lower orders are recalculated in the new vertical datum, so all benchmarks kept in the dataset of geodetic points have a newly determined height. The differences in heights between the old and the new height systems range from 1.4 cm to 30.8 cm.

In this article, an overview of the height geodetic data of Slovenia that were determined on a basis of observations from various tide gauges along the Adriatic coast is presented. This is followed by the definition of the Koper height geodetic datum as a part of a new height system of Slovenia. The height datum was determined on the basis of observations at Koper tide gauge, the rate of sea level change in Koper, and taking into account the local stability of the tide gauge.

In coordinate calculation from terrestrial measurements, the reduction due to the Earth's gravity field should be one of the main topics of consideration. The problem is of extreme importance especially in steep areas, where geoid surface is not parallel to the rotational ellipsoid. In this, the knowledge of the deflection of the vertical is significant. There are two ways for its acquisition: from the comparison of astronomic versus geodetic coordinates, or from the indirect way of calculation by using global, regional, or local geoid models. This paper reviews the deflection of the vertical and its use at the steep area under Krvavec. The computation followed from three models, EGM2008 and two Slovene models: the current SLOAGM2000 and the test model SLOAGM2010. In addition, the local geoid model was established from the ellipsoidal and the normal-orthometric heights. Significant differences in vertical deflection components originated from the EGM2008. We can confirm the expectation that in steep areas it is necessary to consider the geoid inclination. The best way to do this is the local geoid surface determination from the ellipsoidal in physical heights. In other cases, local geoid models are still appropriate. Contrary, we should avoid using global models because of their lower resolution.

The existing Bouguer anomaly map, which covers the territory of the Republic of Slovenia is a few decades old. Since then, quite a few new gravimetric measurements (data) for the territory of Slovenia as well as high quality digital terrain models that are needed for creating such a map have been made available. The methodology and standards for creating gravity anomaly maps are also changing. Thus, the national Bouguer anomaly map was updated. There were some gross errors detected in the set of old gravimetric data. Additionally, the influence of new updated gravimetric data was analyzed. The comparison of the various maps and the analysis of the influence of input gravimetric data indicates that the new gravimetric data of Slovenia has a significant influence on the creation of the gravimetric anomaly maps for Slovenia (even over 30 mGals at some points).

Tide gauges are used to assess sea level changes. Usually, they are placed on the coast (piers), which can be unstable. Consequently, the vertical movement of the tide gauge should be included in the series of observations. The paper deals with the stability of the tide gauge Station Koper (MP Koper), the stability of which was determined relatively on the basis of the levelling network, which was stabilised nearby. The stability of the individual benchmarks was analysed and the velocity vector of vertical displacement of each benchmark was determined with respect to the benchmark 9000 tide gauge. The stability of the tide gauge was also determined in a global reference system by using the series of GNSS observations of the KOPE continuously operating reference GNSS station. The KOPE station is stabilised at the MP Koper and is included in the Slovenian GNSS network of the SIGNAL continuously operating reference network of permanent stations. The vertical velocity vector of the point KOPE was compared with the vertical velocity vectors at other tide gauges, which are located along the Croatian coast, and the tide gauges in Trieste.

This paper deals with the effects that displacements of the measuring pillar have on precise geodetic measurements. The changes in the position of the control points on the object or its surroundings can only be determined with well stabilized and stable reference points. These points are usually stabilized with measuring pillars which are not always constructed in an optimal manner. If they are placed in a dark tube with a high absorption factor, solar heating on one side of the pillar can cause the pillar to deflect considerably due to the temperature difference on the two sides of the pillar. This paper presents the influence of such a displacement, if the pillar is a survey point, orientation point, or control point. We show that even small displacement of the survey point can have important influence on all measurements and that the error in some cases significantly increases, e.g., if the standard deviations of the coordinates of the survey point are 1 mm and their covariance is assumed to be zero, the standard deviation of the distance between measured and exact position of the control point exceeds the value of 2.2 mm.

Technologies of massive spatial data acquisition from air, compared to a classical terrain measurement, enables an acquisition of large amounts of data in shorter time and with comparable quality. Unmanned aerial vehicle (UAV) photogrammetry is increasingly used in the area of the earthwork volumes determination of landfill or excavation of the building material. Dense multi-image matching obtains high-density point cloud. The input data for the earthwork volumes calculations is a filtered point cloud. The earthwork volume calculations are calculated with the method of surface comparisons of two term measurements, created by a triangulated irregular network (TIN) or grid network. The impacts of different methods for surface interpolation and grid cell size on the earthwork volume calculation are analysed. Reference quantity is the volume, calculated from TIN surfaces. Good interpolation methods and appropriate grid cell sizes are determined with the comparison of volumes from grid and TIN surfaces. The difference between volumes should not exceed 5%.

A point cloud is the result of laser scanning; in the case of terrestrial laser scanning, the point cloud is composed of points scanned from one or more positions. To register these points into one point cloud, so-called tie points are needed; these may be object points (natural targets) or selected stabilized targets (artificial targets). Spherical targets are often used as artificial targets; these must have their centre coordinates and radius determined. The centre coordinates of a sphere are calculated on the basis of scanned points on the spheres’ surface. This paper presents two procedures for determining the best reflection region on the sphere to determine its parameters, and the procedure for determining the optimal distance between the scanner and sphere.The best reflection area on the sphere is determined in two ways. The first is based on minimizing the difference between sphere radii when, in the adjustment process, the radius of the sphere is treated as a known and unknown quantity. The second is based on the standard deviation of the sphere’s centre coordinates at the independent determinations of sphere parameters from randomly chosen scanned points on the sphere surface. For each of the spheres, the best ratio between the laser beam footprint area and the target surface area is calculated for the optimal combination of scanning distance and region. For the best combination of scanning distance and region, we chose the one with the smallest standard deviation of the sphere centre coordinates.

To perform geodetic measurements of displacements of the ground and manmade constructions, stabilised reference points are needed from which control points on the object or its surroundings could be measured. Reference points are most commonly stabilised with reinforced concrete pillars; however, they are not always constructed in an appropriate manner. The influence of temperature variation within a pillar on the position of the fixed screw for forced centring is not negligible and should be considered when performing precise measurements. In this research paper, the displacement of a pillar was calculated as a result of the temperature changes in the pillar, and then an experiment was performed in which the pillar was heated from one side, and the horizontal displacement of the fixed screw for forced centring was measured. Both, calculations and measurements, show that at a temperature difference of 16.2 °C, the fixed screw on a 1.5 m high pillar moves by approximately 1 mm, which is a displacement that should be taken into account in precise measurements.

Po poplavah, ki so prizadele Slovenijo v septembru 2010, je Inštitut za vode Republike Slovenije z GNSSvišinomerstvom določil višino geodetskih točk, ki so bile uporabljene za določitev višine poplavne vode na Ljubljanskem barju in v Ljubljani. Višine točk, določene z GNSS-višinomerstvom, smo kontrolirali s trigonometričnim višinomerstvom, z navezavo na reperje mestne nivelmanske mreže Ljubljana. Analizirana je natančnost določitve višin točk in določena razlika med višinami točk, ki so bile določene z GNSS- oziroma trigonometričnim višinomerstvom ; After the floods that hit Slovenia in September 2010, the Institute for Water of the Republic of Slovenia measured the heights of geodetic points (with the GNSS levelling method) used to determine the height of flood water on the Ljubljana moor and Ljubljana. The heights of these points were controlled by trigonometric levelling with connections to the benchmarks of the city levelling network of Ljubljana. An analysis of the accuracy of determining the heights of the points and the differences between the heights of the points, which were determined by GNSS and trigonometric levelling, are presented.

V prispevku je predstavljen predlog za novo oštevilčevanje nivelmanskih poligonov in reperjev. Obravnavana je tudi analiza natančnosti izmerjenih višinskih razlik, opravljena na podlagi odstopanj obojestransko merjenih višinskih razlik in odstopanj pri zapiranju nivelmanskih zank. Na podlagi izravnave nivelmanske mreže in nivelmanskih poligonov je analizirana tudi natančnost na podlagi popravkov merjenih višinskih razlik in izvedena ocena natančnosti določitve nadmorske višine reperjev ; This paper presents a proposal for a new numbering of levelling polygons and benchmarks. Furthermore, an accuracy analysis is done with regard to: measured height differences, residuals calculated from differences of the forward and backward runs, residuals from loop closures, and results from network adjustments.

V okviru projekta Vzpostavljanje evropskega prostorskega referenčnega sistema v Sloveniji je bila izračunana tudi ploskev testnega geoida. V prispevku bo predstavljena primerjava določitve geoidnih višin iz geoida 2000 in testnega geoida iz leta 2010. Analizo natančnosti ploskev geoida Slovenije smo opravili s primerjavo geoidnih višin, ki jih dobimo kot razlike merjenih eliposoidnih in nadmorskih višin (»merjene geoidne višine«) in tistih, ki jih interpoliramo iz modelov. Primerjali smo »merjene« in interpolirane geoidne višine na 352 GNSS/nivelman kontrolnih točkah. Z izračunom ploskve testnega geoida smo pridobili možnost predhodne analize kakovosti prihodnjega geoida, ki je zelo pomembna za izvajanje GNSS-višinomerstva v geodetski praksi ; This paper presents a quality analysis and comparison of two height reference surfaces. The first is the actual geoid model from the year 2000, and the second is the test geoid model determined in the frame of the project Establishment of the European Reference System in Slovenia. Quality analysis is based on the comparison of geoid heights determined from measured ellipsoidal and mean-sea-level heights and geoid heights interpolated from the model. A comparison was made on 352 GNSS/levelling points.

SI: Geodetske metode so eden od možnih načinov za ugotavljanje stabilnosti geotehničnih objektov. Spremljanje premikov geotehničnih objektov je zaradi velikosti objektov in pričakovanih premikov nekoliko specifično. Pričakovana velikost premikov določa potrebno natančnost določitve premikov, velikost objekta pa določa metodo geodetske izmere. V osnovi izbiramo med terestričnimi metodami in metodami GNSS (globalni navigacijski satelitski sistem. Ker za izvajanje geotehničnih meritev ni ustrezne zakonske podlage, predstavljamo posebnosti posameznih metod in navajamo splošna priporočila za izvedbo geodetskih postopkov pri spremljanju premikov geotehničnih objektov. Priporočila so namenjena projektantom geotehničnih objektov in izvajalcem geodetskih del ter investitorjem, ki jim lahko olajšajo nadzor nad izvajanjem geotehničnih projektov.ENG: Geodetic methods are one of the possible means of determining the stability of geotechnical objects. The determination of the displacements of the geotechnical objects is specific due to the size and the expected displacements. The expected size of the displacement determines the necessary precision of the displacement determination, whereas the size of the object determines the method of the geodetic measurement. We choose either the terrestrical or the GNSS methods. There is no relevant legal framework for geotechnical measurements. For this reason,we present the characteristics of the single methods and suggest general recommendations regarding the implementation of the geodetic procedures when monitoring the displacements of the geotechnical objects. The recommendations are intended for geotechnical engineers planning the geotechnical objects and the operators of geodetic measurements and investors. The recommendations the facilitate supervision of the geotechnical projects.

V prispevku so obravnavane aktivnosti geodezije za potrebe določitve premikov zemeljske skorje, lokalnih premikov zemeljske površine ter premikov in deformacij grajenih objektov. Določitev premikov v terestrični horizontalni mreži, terestrični višinski mreži in mrežiGNSS obravnavamo na dveh stopnjah natančnosti. Dejavnosti geodezije v geotehniki so razložene v besedilu prispevka in nazorno prikazane v preglednici. Pričujoči prispevek je skupaj s prispevkom Geodezija vgeotehniki, objavljenim v Geodetskem vestniku 54(1), zaokrožena celota. ; This paper deals with surveying activities in order to define the displacement of the Earth’s crust, local displacements of the Earth’s surface, and the displacement and deformation of constructed buildings. The determinations of horizontal movements in the terrestrial network, in the terrestrial altitude network and in the GNSS network are dealt with at two levels of accuracy. Geotechnical surveying activities are explained in the paper and demonstrated in the table. The paper Geodesy in geotechnics, publishedin Geodetski vestnik 54(1), and this paper present an integral whole.

SI: V prispevku je predstavljen postopek izračuna vrednosti težnega pospeška na točkah nove osnovne gravimetrične mreže Slovenije. Gravimetrična opazovanja so bila opravljena leta 2006 z dvemarelativnima gravimetroma Scintrex CG-3M. Prikazani so postopki, ki so bili uporabljeni pri obdelavi merskih vrednosti. Sama izravnava opazovanj v gravimetrični mreži je bila izvedena v dveh fazah. V prvi fazi so opazovanja v mreži 0. reda izravnana po načelu prostemreže, v drugi fazi je bila opravljena klasična izravnava v mreži 1. reda. Podane so končne vrednosti težnih pospeškov na točkah gravimetrične mreže. Izvedena je tudi analiza rezultatov glede na stari potsdamski sistem, v katerem so bili opravljeni vsi predhodniizračuni gravimetričnih meritev v Sloveniji. Na podlagi teh analiz je določena enačba za transformacijo težnih pospeškov med potsdamskim sistemom in sistemom IGSN71(International Gravity Standardization Network 1971). Nova osnovna gravimetrična mrežaSlovenije je kakovostna podlaga za vse nadaljnje potrebe, ki so povezane s poznavanjem težnega pospeška na območju Slovenije.EN: The paper presents the determination of gravity values on stations of the new gravity network of Slovenia. The measurements were performed in autumn 2006. The procedures comprise the computation of reductions of gravity observations and several phases of adjustment. In the first step the zero order gravity network wasadjusted with subsequent adjustment of the complete gravity network, where absolute points were held as fixed points. The adjusted gravity values on some points were compared to gravity values referring to Potsdam Gravity System and transformation equationwas determined (Potsdam into IGSN71). It could be stated that the new Slovenian gravity network provides a solid basis for all further gravimetric surveys in Slovenia.

Establishing recent displacements along faults is an important and delicate task. Larger faults are accompanied by broader fault zones that require a specificapproachtogeodeticmeasurements of fault block displacements. The vector of fault block displacements, or resultant, is a vector sum of differential displacements within the fault zone. For the purposes of recording the displacements we propose the stabilization of a geodetic network of points positioned in fault blocks outside the fault zone, whereby the displacements would be manifested in the deformation of the network. The resultant displacement vector can then be derived from the latter deformation, and from that, the dip and strike of the fault zone as well as the extent of the displacement.

Several important geological structures in the western Slovenia were identifiedas active and their activity was quantified. Geologic interpretation is based on the analysis of repeated leveling line campaigns data along the Sečovlje–Bled polygon. Taking intoaccount the limitations of the method – only the vertical component of displacement is measured – the following structures were identified as active:a juvenile syncline between Strunjan and Koper, the Kras Imbricate Structure, the Diva~a fault, the Ra{a fault, the Southalpine Front and the Julian Alps thrust. Vertical movement rate is relative, calculated with respect to the benchmark in Sečovlje. The largest uplift rate difference between Sečovlje and Bled is 7 mm/a.Vertical Geodynamic Activity (VGA) is introduced as a link between geologic interpretation of geodetic measurements on one side and possible applications on the other as well as a mean of comparison between tectonically active regions.

The paper gives the outline of the modern physical height systems which are based on levelling and gravity surveys. Also, the Slovenian vertical networks are presented (vertical datum and height system) with all their drawbacks. The adoption of the new modern height system and determination of the new (quasi)geoid would enable a widespread use of GNNS levelling. The possible use of the new national vertical datum or European vertical datum is discussed.

The project of a new gravimetric network of Slovenia is presented. It resulted from the needs for the new gravimetric and height systems of Slovenia, all parts of the new national coordinate system. The project of the gravimetric network is based on analyses of old gravimetric network and surveys carried out at the territory of the Republic of Slovenia. Besides, the geological assessment of suitability of the preserved and new planned gravimetric stations was completed.

Under the auspices of the Environmental Agency of the Republic of Slovenia a new state-of-the-art tide gauge station was set up in Koper. The paper presents the geodetic works that were performed in order to determine the position of the tide gauge station in theterrestrial reference system. All measurements were carried out during the testing period of the tide gauge, that is, from the end of 2005 until the begining of 2006.

Anomalies in vertical displacement rates related to recent geodynamics were determined between Rateče and Ljubljana by comparing leveling line data with topography of the Sava river longitudinal profile. Beside the general trend showing increase of verticaldisplacement in the S-N direction, segmentation of the area is noted. The later suggests that active geological structures exist in the northern part of the Ljubljana basin and in the Upper Sava valley respectively.

In the article, the improvement of the levelling network of Slovenia is presented. Analyses of the state of benchmarks are made (number of benchmarks, applicability, art of stabilizations, time of benchmark stabilization). The analysis of the problems and deviations that have appeared in the levelling network is shown in detail. Described are also the procedures of the improvement, recent calculations and the condition of the levelling network after the calculation.

The paper presents a project of renovating a levelling line from Hydroelectric Power Plant Medvode to Hydroelectric Power Plant Vrhovo. The levelling line is situated along the Sava River. A new height of benchmark was needed as a vertical reference system for the project building up a new HPP between the previously mentioned HPP. Further, the paper presents processing data on measurements (scale and temperature corrections). Gravimetric measurement was performed due to the determination of the geopotencial number and dynamic and normal heights. Slovenian official vertical system contains normal orthometric heights so we also calculated normal orthometric heights. Moreover, the article discusses the accuracy of measurements (levelling and gravimetric) and analyses height calculated in different vertical systems and vertical movements along the levelling line. Article in English Įvairių aukščių sistemų prie sava upės analizė Santrauka. Pateikiamos niveliavimo renovacijos projektas nuo Medvode iki Vrhovo hidroelektrinių. Niveliaciniai ėjimai projektuojami išilgai Savos upės. Nauja niveliavimo markių sistema tarnaus kaip referencinis vertikalus tinklas tarp minėtų hidroelektrinių. Toliau numatomas matavimo duomenų apdorojimas (mastelio ir temperatūros pataisos). Numatomi gravimetriniai matavimai, reikalingi nustatant geopotencialą ir dinaminius bei normalinius aukščius. Slovėnijoje naudojama normalinė ortometrinė aukščių sistema, todėl mes skaičiuojame normalinius ortometrinius aukščius. Pateikiami matavimų tikslumo skaičiavimai (niveliavimo ir gravimetriniai), apskaičiuotų aukščių analizė skirtingose aukščių sistemose ir niveliavimo ėjimo vertikalūs judesiai.