The determination of the vertical displacements in the levelling networks on the area of the

In graduate thesis proceedings, results and ascertainments of determination of the vertical displacements in levelling networks on the area of the Ljubljana basin are presented. Vertical displacements are consequence of geotectonic movements and can be measured with leveling method. This is the most accurate and very easy method for determination of height difference between two geodetic points. Vertical displacements of Ljubljana city levelling network are determine with comparison between four term measurements. The Ljubljana city leveling network includes the city of Ljubljana with its surroundings. Adjustment proceedings and results of individual leveling networks or leveling lines are presented. Results of adjustment are processed with two softwares. Unstable vertical points are determined in software PREMIK, stability of leveling network is statistically tested with software DAH (Deformation Analysis Hannover)

Status of the new height system development

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

Impact of the grid cell size and interpolation methods on earthwork volume calculation

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

Quality analysis of the sphere parameters determination in terrestrial laser scanning

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

Analiza stanja pri uvajanju sodobnega višinskega sistema : Status of the new height system development

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

Analysis of the flood in Ljubljana and on the Ljubljana moor \ud

After the floods that hit Slovenia in September 2010,\ud the Institute for Water of the Republic of Slovenia\ud measured the heights of geodetic points (with the\ud GNSS levelling method) used to determine the\ud height of flood water on the Ljubljana moor and\ud Ljubljana. The heights of these points were controlled\ud by trigonometric levelling with connections to the\ud benchmarks of the city levelling network of Ljubljana.\ud An analysis of the accuracy of determining the heights\ud of the points and the differences between the heights\ud of the points, which were determined by GNSS and\ud trigonometric levelling, are presente

Comparison of Valentin Hodnik’s Stone Model of Triglav and the Actual Shape of the Mountain

In Ribčev Laz near Lake Bohinj there is a model of Triglav, the highest mountain in Slovenia. Made of stones, it is the work of the painter Valentin Hodnik from Bohinj. Although it is a work of art, we wanted to evaluate the correctness of its shape compared to the actual mountain. We photographed it and created a point cloud model using the Structure from Motion process (SfM). By transforming the point cloud to actual size, we were able to compare it with the actual shape of the Triglav mountain range obtained from Laser Scanning of Slovenia (LSS). As expected, the shape of the model varied considerably from the actual shape of the mountain, and the scale of the individual slopes and ridges was not the same. For a qualitative evaluation of the model, we calculated the distances between the transformed model and actual surface. The average absolute distance between the nearest points in both point clouds was 41.8 m (6 cm at a built-model scale) with a standard deviation of 38.0 m (5.4 cm). The results are represented by a picture of absolute distances. We also produced a smaller 3D print of the Triglav model and the actual shape of the mountain

Comparison of Valentin Hodnik’s Stone Model of Triglav and the Actual Shape of the Mountain

U Ribčevom Lazu kraj Bohinjskog jezera nalazi se maketa Triglava, najviše planine Slovenije, izgrađena od kamena, rad slikara Valentina Hodnika iz Bohinja. Iako je umjetničko djelo, odlučili smo procijeniti točnost njezinog oblika. U tu smo svrhu snimili maketu fotografskim aparatom i korištenjem procesa struktura iz kretanja (SfM) stvorili oblak točaka. Pretvarajući taj oblak točaka u stvarnu veličinu planine, uspoređivali smo oblik makete sa stvarnim oblikom planinarskog područja Triglava dobivenim iz podataka laserskog skeniranja Slovenije (LSS). Kao što se očekivalo, oblik makete značajno odstupa od stvarnog oblika planine, a ni mjerilo pojedinih padina i grebena nije isto. Za kvalitativnu procjenu makete izračunali smo udaljenosti između najbližih točaka transformiranog modela makete i stvarne površine. Prosječna udaljenost između najbližih točaka oba modela je 41,8 m (6 cm u mjerilu makete) sa standardnom devijacijom od 38,0 m (5,4 cm). Rezultati su prikazani s pomoću slike apsolutnih udaljenosti. Osim toga, izradili smo i umanjen 3D otisak makete Triglava i stvarnog oblika planine.In Ribčev Laz near Lake Bohinj there is a model of Triglav, the highest mountain in Slovenia. Made of stones, it is the work of the painter Valentin Hodnik from Bohinj. Although it is a work of art, we wanted to evaluate the correctness of its shape compared to the actual mountain. We photographed it and created a point cloud model using the Structure from Motion process (SfM). By transforming the point cloud to actual size, we were able to compare it with the actual shape of the Triglav mountain range obtained from Laser Scanning of Slovenia (LSS). As expected, the shape of the model varied considerably from the actual shape of the mountain, and the scale of the individual slopes and ridges was not the same. For a qualitative evaluation of the model, we calculated the distances between the transformed model and actual surface. The average absolute distance between the nearest points in both point clouds was 41.8 m (6 cm at a built-model scale) with a standard deviation of 38.0 m (5.4 cm). The results are represented by a picture of absolute distances. We also produced a smaller 3D print of the Triglav model and the actual shape of the mountain

What about topography? Status and quality of topographic data in Slovenia

Topographic data, an important part of the National Spatial Data Infrastructure, have been given serious attention since Slovenia's independence. It has become publicly available, updated and harmonised. Financing of topographic data in Slovenia has significantly decreased over the previous decade. As a result, the present status is far from acceptable or expected. The current status of the topographic data, as well as its quality and usability for potential users is discussed in this article. The overview starts with basic source data, aerial surveys, photographs and orthophotos. The quality of orthophotos largely depends on the DTM quality. Topographic data is nowadays organised in thematic datasets (geographical names, building cadastre, etc.) or joined in datasets of different levels of accuracy and details. The status in Slovenia is compared to those in some neighbouring and other comparable countries