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The reliability of adjustment results in geodetic networks is of critical importance for the investigation of geodynamic processes such as deformation and tectonic movements, where vertical displacements represent a key monitoring component. Precise levelling remains the fundamental technique for such observations. Recent studies indicate that the adjustment of all possible combinations of measurements can yield more accurate and reliable results compared to the classical least squares adjustment of levelling netw...

The maintenance of a modern vertical reference system in Bulgaria, aligned with the European Vertical Reference System (EVRS) standards, is directly dependent on the precise knowledge of the Earth's gravity field. The research presented in this paper is motivated by the 5th cycle of the 1st order National Leveling Network (NLN) re-measurement, initiated in 2021, which involves complex observations across 55 leveling lines. The primary objective of this study is to evaluate the extent to which existing gravity reso...

This paper is focused on the verification of two quasi-geoid models for the territory of Bulgaria (the model integrated into the Geodesy, Cartography and Cadastre Agency (GCCA) official product for the transformation of geodetic data and a model derived using the GNSS/levelling method) through direct geodetic measurements. The study was developed in the framework of the current 5th cycle of the 1st Order National Levelling Network (NLN), conducted in accordance with the requirements of the new 2021 Instruction [1]...

The monitoring of the construction behavior is one of the important activities carried out to determine the state of construction, subject to various natural and anthropogenic actions at a given time. In Romania, the activity of rockfill dams monitoring is regulated according to the importance category (A, B, C). The Rausor Dam is located downstream of the confluence of the River Rausor with the river Targului, which springs from the Iezer - Papusa Mountains in the central part of Romania. Being part of importance...

Civil aircraft navigation uses specific procedures for the continuous determination of the aircraft position using the path and distance traveled in the considered time interval as calculation elements. Throughout the route, errors must be estimated that are generated by a series of parameters such as: hydrometeorological conditions, air current direction, declination, geoid parameters, the ship's nautical qualities and the response mode of the navigation equipment. The indications of the magnetic compass must be ...

The aim of the article is to present selected experience with updating the digital technical map (DTM) dataset in the Czech Republic after 2 years of its widespread introduction into operation. The subject of the analyses was the methods of initial filling of the basic spatial situation (ZPS) data with new mapping of land roads and defined territories of technical infrastructure administrators. When updating the ZPS, accuracy problems of vectorization from LIDAR mobile mapping data and problems of the results of p...

Spatial data infrastructure is an essential tool for the management, planning, and analysis of sustainable development. The Latvian ecosystem, which consists of numerous decentralized resources, has successfully established a foundation by fulfilling the requirements of the European Union's INSPIRE and Open Data directives. The transition from a culture of viewing 'paper maps' to the automated machine processing of standardized, vectorized, and semantically rich data represents the primary benefit. To evaluate and...

UAV photogrammetry is well established in Slovak geodesy across all aspects of surveying work. To a lesser extent, it is also used for the purposes of the Slovak Land Administration System (LAS). The aim of this study was to analyze the advantages and disadvantages of obtaining coordinates of breakpoints of ownership boundaries from data acquired by UAV photogrammetry. Data collection took place in 2025 in the cadastral area of Pac, covering an area of 0.703 square km. The survey work lasted 4 hours using a DJI Ma...

This paper investigates the potential of Global Navigation Satellite System (GNSS) technology for monitoring vertical displacements in areas affected by underground mining and evaluates its combination with precise geometric leveling. The study is based on repeated measurements carried out in the Stonava locality (Czech Republic), where intensive deep coal mining induces significant surface subsidence reaching up to several decimeters per year. The main objective is to assess the accuracy of GNSS-derived heights, ...

The aim of the article is to present modern geodetic methods used for surveying sacral buildings. These are terrestrial surveying, photogrammetry and drone images. When surveying the building, the digital sketch method was used, which, in addition to the geometry, also captures the topology of the resulting drawing of the surveyed object. The benefit of this method is the automated drawing of a wireframe model of the building in a CAD application. The platform used is QGIS with Python language support. The advanta...

The statistical characteristics of section discrepancies and standardized section discrepancies derived from the Third Levelling of Bulgaria are examined in detail. The computed excess kurtosis values are minus 0.44 and minus 0.56, respectively, with standard deviations of 0.07. These results clearly indicate a notable departure from the normal distribution, for which the excess kurtosis is equal to zero. This finding suggests that the conventional methodology for defining permissible limits between measurements, ...

This paper discusses the relevance of the classical adjustment weights for the highest-order geometric levelling network. The commonly used weights are inversely proportional to the length of levelling lines. The argument behind this choice is the assumption that the accuracy of measured elevations is a function of the square root of the levelled route. Therefore, the longer the line, the less its weight in the adjustment of the network. However, there are often events where the measured elevations of long lines a...

In the era of advancing digitization, the application of Building Information Modeling (BIM) technology in the construction industry is increasingly evident at advanced level. However, the use of BIM tools during the operational phase of buildings-beyond traditional design and construction-remains a niche area, with integrated digital facility management practices still limited in adoption. In this article, the authors focus on presenting an example of pilot project of implementation of the digital Common Data Env...

It is well established that the farther a benchmark is from the datum point in a leveling network, the greater its standard error of adjusted height tends to be. To explore the optimal datum point location for minimizing height uncertainty, we performed 11 separate adjustments of the Second Bulgarian Leveling Network. Each adjustment used a different nodal benchmark as the datum point. While all adjustments yielded identical benchmark elevations and the same mean adjustment error of 2.14 mm/km^0.5, the sum and ave...

Conventional salt mining creates large voids that disrupt geomechanical equilibrium, inducing subsidence pressures from overlying strata. This process, known as convergence, is the time-dependent closure of excavated spaces caused by salt-s viscoplastic behavior. Continuous convergence monitoring is critical for early detection of excessive strain, enabling timely mitigation to maintain structural stability and prevent hazards like water ingress and flooding. Due to the slow deformation rates of halite formations,...

This article examines the impact of electric and electromagnetic fields on the accuracy of GNSS technology, particularly in environments with overhead high-voltage and power lines. Although this factor is often overlooked, it can significantly affect the quality of received signals and, consequently, the accuracy of measurements. Electromagnetic interference caused by the presence of power lines can lead to signal distortions, reduced positioning reliability, and, in some cases, complete signal loss. The study foc...

Sea level change and global sea level rise are slow but persistent changes. They should be evaluated as a sign of ongoing climate changes. The Black Sea is a semi-enclosed sea, with the only connection to the world's oceans being the narrow Bosphorus Strait. The influence of climate changes in such an environment will be grater. Sea level observations on the Bulgarian part of the Black Sea are carried out by numerous tide gauge stations. The most indicative of them, with the most complete set of measurements, is t...

The geometric levelling of the highest order has been the main method for many scientific and engineering tasks for more than 150 years. One of them is the monitoring of the recent vertical movements of the Earth-s crust. In order to understand the low of accumulation of the discrepancies in levelling lines, many investigators have planned and performed various experiments and analysis through the years. As a result, the systematic effects of many sources of measurement errors have been studied, and partly or full...

This paper presents the monitoring of an eroding phenomenon (gully) near Ciurila, Cluj County, Romania, using UAV (Unmanned Aerial Vehicle) and GNSS (Global Navigation Satellite System) technologies. In this sense, the monitoring results through sustainable and non-invasive technologies are presented, following four cycles of observations, carried out between June 2019 and April 2021. The paper aims to present the advantages and limitations of such a study, as well as the importance of monitoring erosion phenomena...

Constructions extending over large areas or distances raise problems regarding their setting out, because these elements are determined in the official projection of Romania, namely the 1970 Stereographic map projection. For the territory of our country, this produces distortions from -25 cm/km to approximately +64 cm/km in terms of distances and between -5 sq. m/ha and +12.76 sq. m/ha in terms of areas, depending on the distance from the projection pole and, implicitly, from the circle of zero distortions. For th...

The issues related to the use of products generated from Continuously Operating Reference Station (CORS) for precise positioning are the main focus of the study. Geodetic measurements were conducted at a real site, and different types of data provided by commercial CORS networks were compared - Network Real Time Kinematic (Network RTK) via VRS, generated data for subsequent processing (Virtual Rinex), and raw data from a physical station. The current national regulations, as per [1] , were adhered to, and the aim ...

Due to usage, handling, and improper storage, measuring tapes undergo changes in their condition over time. For this reason, regular inspection is necessary to ensure the desired quality of results, aiming to verify the accuracy of the tape and its usability in practice. During the calibration of measuring tapes, the position of the scale divisions on the tape is evaluated using a device known as a horizontal comparator. This device consists of a linear base on which a carriage with evaluating equipment, in our ca...

Land administration system in Slovakia is a large system. Many incomplete data and errors have been incorporated into its content since 1850. Most problems in the field of land administration system are solved by judicial proceedings, in which the expert testimony is required to reach the conclusion. The gathering of data about a particular land parcel consists of investigation of documents and maps. The investigation of map documents is very important for the whole process. The derivatives of these maps are store...

The paper presents a quality evaluation of the kinematic model concerning the relative height movement of the Earth-s crust that refers to the territory of the Republic of Croatia. This kinematic model enables determination of vertical displacements and movement speeds of discrete points on the Earth-s crust. So far, the quality of the model has been rated only for certain parts of the Croatian territory, but this paper shows the results of the model-s quality evaluation for the entire territory of the Republic of...

Precise levelling networks play an important role in the research of many scientific processes, e.g. the recent crustal movements, the change of ocean and sea levels, geoid or quasi-geoid, etc. Their appropriate adjustment goes through the choice of suitable weights, which have physical common sense and minimize the standard errors of the adjusted heights. The conventional weights are supposed to be inversely proportional to the length of levelling lines, due to the assumption that the accumulation of errors in th...

Underground mining operation in salt deposits requires special control over rock mass stability. Changes in stress within the rock mass cause gradual convergence of underground workings. A slow convergence process with a complex spatiotemporal distribution requires the measurements with high accuracy, which is carry out on a well-planned spatial distribution of observation network. The aim of the study was to present the procedure of designing and implementing observations of convergence in salt caverns within a s...

The study of a gravimetric network is closely connected with determining the value of the drift on the gravimeter scale (zero-point drift; drift). The realization of a great number of over-measured quantities makes preliminary processing of gravity measurements a hard, slow, and delicate process. The main purpose of this research is to investigate a method that would simplify the overall technology of gravimetric measurement and post-processing of the results obtained. A modification of the commonly adopted adjust...

Mobile handheld laser scanning is already an established technology in today's surveying practice. Mobile handheld scanners are mostly used for surveying and 3D rendering of indoor spaces. However, the subject of this paper will be the area of real estate cadastre. The aim of this paper is to verify the capabilities of mobile handheld laser scanning technology for cadastre of real estate purposes. The paper will focus specifically on surveying activities related to the production of a survey sketch for designation...

Research Object and Relevance. The main components of the strain tensor and their accuracy assessment are the research objects in this work. When conducting monitoring using geodetic methods, it is usually not enough to determine only the displacements of reference points; it is also necessary to determine the presence and magnitude of deformations. This task is directly related to the accuracy assessment of such characteristics as principal strains, dilatation, shear strains, and rotation. Research Methods. In co...

The use of digital twin models in immovable culture heritage enables better decisionmaking about preventive maintenance, heritage management, and interpretation, as well as accurate digital documentation. This publication discusses an approach for creating a digital twin using different methods of spatial data acquisition: close range terrestrial digital photogrammetry, aerial digital photogrammetry and terrestrial laser scanning. The "Holy Transfiguration" Church in Pomorie, Bulgaria which is the oldest functioni...

In recent years GNSS studies play an increasing role in studding of natural risk hazards and active tectonics. The area of Sofia is part of the broad South-Balkan Extensional Tectonic System. This highly populated area of economic significance, even showing to be not so active as other parts of the System is also affected by natural hazards, as active seismicity, landslides, rock falls, debris, etc. GNSS studies are extremely important for understanding of natural hazards and recent geodynamics of the area, especi...

This article outlines time series analysis of sea level data from Varna tide gauge stations, to solve for short and long term sea level variations. The period of observations span to 1928 - 2022. Monthly sea level data were processed using a linear regression model includes mean sea level, trend, annual, semiannual and decadal variations. Analysis of monthly sea level data for period 1928-2022 clearly indicates annual and decadal variations of mean sea level. Hourly sea level data of radar tide gauge include the p...

The Cultural Heritage Act regulates the preservation and protection of the cultural heritage of the Republic of Bulgaria, and the State ensures the protection of cultural heritage regardless of its location. The procedure for identifying, declaring and granting the status of sites as immovable cultural property, as well as the procedure for establishing temporary protection regimes for declared immovable cultural heritage sites and for the protection regimes for immovable cultural property, are also laid down in s...

The monitoring of geodynamic processes with modern GNSS technology in the area of Sofia and Southwest Bulgaria has been going on for more than 25 years. To investigate modern crustal motions in the area, GNSS data obtained between 1996 and 2022 are analyzed to obtain the velocity field for southwestern Bulgaria. Every year, measurements are carried out on a part of the points, and the last measurements were carried out in 2022. For the entire period, monitoring covered 28 stations. To evaluate the new result for t...

In geodetic practice, the definition of spatial objects in relation to a uniform and reliable coordinate system is of paramount importance. In the Republic of Bulgaria by the Decree of the Council of Ministers No 153 of 29 July 2010 and Regulation No 2 of 30 July 2010 on the Definition and Maintenance of the Bulgarian Geodetic System 2005 (BGS2005). The points of the State GPS network (SGPSN), defined in the ETRS89 coordinate system, realization ETRF2000, epoch 2005.0 represent a realization of BGS2005 and their i...

The purpose of this study is the analysis of the dynamics of tectonic movements accompanied by two strong seismic events that occurred in the Durres area (Albania) in September-November 2019, through the use of GNSS technology, applied to national permanent satellite geodetic networks. Previous studies have been carried out on our study area by foreign authors from Croatia, Greece, and Italy. For our study case, we relied on geodetic weekly data secured from the Bulletins of Italian and Austrian stations, BSW52, o...

In order to study and analyze the state of the State Gravimetric Network for the territory of the Republic of Bulgaria, relative gravimetric measurements were carried out for part of the country. The studied territory covers 9 points of the reference gravimetric network. The gravimetric measurements were designed and implemented according to the realized gravimetric lines between them and gravity differences along the gravimetric lines were calculated. The obtained gravity differences are compared with the same fr...

In this study, we aim to demonstrate the change in the topography of the sea floor as a result of the sedimentation of rivers. The study area is the Divjaka Bay, bounded to the north by the delta of the Shkumbin River and to the south by the delta of the Seman River, on the Adriatic coast of Albania. The method used is the Integrated Satellite Bathymetric Surveying method. The monitoring period extends from 2017 to 2020, based on 4 monitoring campaigns. The longitudinal bathymetric profile extends northsouth, in p...

The field of construction is currently one of the most stable and active fields of activity. It presents complex activities that are done in phase and chronologically until the end of completion execution stage. Realization of the foundation or its characteristic elements it includes a number of preparatory activities such as: land preparation and release of various tasks, shoveling and ground consolidation. The type of consolidation it is chosen according to the depth of the escape and It is about choosing a supp...

According to the Bulgarian legislation, the boundaries of the specialized objects of the Black Sea coast - sea beaches, coastal and coastal protection systems and facilities, coastal lakes, lagoons, limanas and wetlands, as well as sand dunes are determined by direct geodetic measurements and are reflected in the cadastral map and the property register, i.e. specialized maps and a specialized register shall be drawn up in accordance with a by-law (ordinance) on the conditions and procedure for the commissioning, c...

In addition to its main purpose: establishing and maintaining the parameters of the height system for the territory of a given state (country), state levelling networks also serve to establish (register) the contemporary (recent) vertical movements of the Earth's crust. The detection of such movements, besides in a purely research sense, is of great practical importance. The displacement of the benchmarks over time plays an essential role in seismic forecasting in the short and long term. Sometimes, not very often...

The article summarizes the main geodetic activities performed in the region of Southwestern Bulgaria to study the modern crustal movements and clarify the geodynamic situation of the region. The study area is bounded to the north of the southern slopes of the Balkan Mountains, to the south to the southern slopes of the Rila Mountains, to the west - the western border of Bulgaria and to the east - the beginning of the Upper Thracian plain. The area has a complex geological structure with many active faults that mus...

The latest amendments to Ordinance 1 on the creation and maintenance of specialized maps and registers of specialized public state property under the Act on the Black Sea coast spatial development create a procedure for changing and periodically updating these specialized maps and registers, as the existing regulation regulated only their creation and acceptance. The change and the periodic updating of these specialized maps and registers are assigned by the Bulgarian Agency for Geodesy, Cartography and Cadastre t...

The new network of permanent GNSS (Global Navigation Satellite System) stations should be established by the end of this year. At the moment, 18 permanent stations are already established. All stations coordinates must be determined following the conditions dictated by the Republic Geodetic Authority of Serbia, i.e., the Rule Book for establishing the GNSS permanent stations network. The coordinates of stations, the final solution, must be calculated from three consecutive uninterrupted daily sessions as a combine...

The article deals with the developing and applying of the mobile mapping system developed at the Department of Surveying of the Slovak University of Technology in Bratislava. The article presents a low-cost mobile mapping system for simultaneous localization and mapping of the indoor environment. Existing systems are costly and have robust construction and high-power requirements, making them unavailable for some applications. The proposed measuring system consists of three orthogonally placed 2D lidars, a robotic...

In 2004, a digital terrain model (DTM) was created in Serbia. It was obtained by vectorizing isohypses on topographic maps with a scale of 1: 25000. The resolution of the digital model of Serbia is 30 m, and the vertical accuracy, as the authors claim, is 10 m. From December 2021, the global model FABDEM (Forest And Buildings removed Copernicus DEM) is available to the public. It was created based on the data of the Copernicus GLO30 model so that data on forests and buildings were removed from it. Important featur...

The purpose of the paper is to perform a topographic lifting and traction of an architectural project for the execution of a Tyrolean that is arranged on various relief forms, in a hilly area, halfway between Timisoara and Lugoj, Timis County, Romania. The development of an adventure park in an area so close to urban settlements has a great impact on the public of all age categories. Children are the main beneficiaries of such objectives because they test their minds and, at the same time, implement an active and ...

The article presents the current state and views of the author in connection with the creation of a Geoinformation system for the territory of Bulgaria within the meaning of the Geodesy and Cartography Act. The provisions of this law on this issue are from its entry into force, i.e. since 2006 and so far, there is no officially published information on actions in this direction, except for the creation and maintenance of Web applications with information on materials and data from the Bulgarian Geocartfond and inf...

This paper covers the activities of creating a database for the study of modern crustal movements in the region of Sofia and Southwestern Bulgaria, including data from GNSS measurements of the geodynamic network and the results of their processing and analysis, data from permanent stations and archive data from Synthetic-aperture radar, processing and obtaining interferometric images. The local archive of GNSS measurement includes: manual sketches of the location of the points; log sheets of the measurement with i...

The Republic of Bulgaria is located on the periphery of the Eurasian tectonic plate, and part of it falls within the seismically active Aegean extensional region [1]. The study of modern crustal movements is important in terms of elucidating the geodynamic behaviour of the country on a regional and global scale. It should be taken into account when establishing and maintaining geodetic networks for high precision applications. It should be noted that for the main carrier of the Bulgarian geodetic system - the Stat...