Geodetic Institute of Slovenia

Ljubljana, Slovenia

Geodetic Institute of Slovenia

Ljubljana, Slovenia
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Mesner N.,Geodetic Institute of Slovenia | Ostir K.,Slovenian Academy of science and Arts
Journal of Applied Remote Sensing | Year: 2014

Segmentation, the first step of object-based classification, is crucial to the quality of the final classification results. A poor quality of the segmentation leads directly to a low quality of the classification. Therefore, it is very important to evaluate the segmentation results using quantitative methods and to know how to obtain the best results. To obtain the best possible segmentation results, it is important to choose the right input data resolution as well as the best algorithm and its parameters for a specific remote sensing application. The impact of the segmentation algorithm, the parameter settings, as well as the spatial and spectral resolution of the data is investigated. To describe these impacts, we performed more than 70 segmentations of a Worldview-2 image. The impact of the spectral resolution was tested with 10 combinations of data on different spectral channels, and the impact of the spatial resolution was tested on an original and downsampled test image to four different spatial resolutions. We investigated these impacts on the segmentation of objects that belong to the classes urban, forest, bare soil, vegetation, and water. The impacts on the segmentation are described using a common methodology for the evaluation of segmentation. © Society of Photo-Optical Instrumentation Engineers.

Triglav-cekada M.,Geodetic Institute of Slovenia | Radovan D.,Geodetic Institute of Slovenia | Gabrovec M.,Anton Melik Geographical Institute | Kosmatin-Fras M.,University of Ljubljana
Photogrammetric Record | Year: 2011

A panoramic, non-metric, Horizont camera has been used for regular, monthly, close-range photography of the rapidly retreating Triglav glacier in Slovenia since 1976. The unfavourable geometry of the convergent images taken from the two camera stations has made any direct stereoscopic observation and recording impossible. The aim of this research was to define the most useful method for acquiring 3D data from these panoramic, convergent images. The Horizont camera was calibrated and three methods were then tested: the generation of pseudo-orthophotographs, the application of 2D clinometry and the interactive orientation of a detailed digital elevation model (DEM) on the images. The third turned out to be the only method suitable for determining the boundary of the Triglav glacier. The interactive orientation of a detailed DEM on the Horizont images is described in detail. The 3D glacier boundary can be acquired from individual Horizont images (camera stations A and B) enabling the computation of the glacier's area and theoretical volume. By repeating the glacier boundary acquisition for different orientation parameters, the standard deviations of the glacier area and theoretical volume were computed. Because of the more precise average area and volume measurements achieved with the camera station B images, only these were chosen for the glacier disappearance study. Every third year between 1976 and 2005 the Horizont images were used to compute the changes in the area and volume of the glacier. The glacier area was found to have reduced to 8% of its earlier size, from 15ha in 1976 to 1·2ha in 2000. However, owing to harsher than average winters since then the decline in the glacier area was found to have slowed in the past decade (2000 to 2009). The glacier's theoretical volume decreased roughly exponentially from 1976 to 2005. © 2011 The Authors. The Photogrammetric Record © 2011 The Remote Sensing and Photogrammetry Society and Blackwell Publishing Ltd.

Krizaj D.,University of Ljubljana | Baloh M.,University of Ljubljana | Zagar T.,Geodetic Institute of Slovenia
Journal of Physics: Conference Series | Year: 2013

A bioimpedance device (BIA) for evaluation of sarcopenia - age related muscle mass loss - is designed, developed and evaluated. The requirements were based on lightweight design, flexible and user enabled incorporation of measurement protocols and WiFi protocol for remote device control, full internet integration and fast development and usage of measurement protocols. The current design is based on usage of a microcontroller with integrated AD/DA converters. The prototype system was assembled and the operation and connectivity to different handheld devices and laptop computers was successfully tested. The designed BIA device can be accessed using TCP sockets and once the connection is established the data transfer runs successfully at the specified speed. The accuracy of currently developed prototype is about 5% for the impedance modulus and 5 deg. for the phase for the frequencies below 20 kHz with an unfiltered excitation signal and no additional amplifiers employed.

Triglav-Cekada M.,Geodetic Institute of Slovenia
Annals of Glaciology | Year: 2013

Triglav glacier is situated on the northeast side of the highest Slovenian mountain peak, Triglav; it is a glacier remnant of the Little Ice Age. Next to Triglav glacier is the Kredarica mountain hut with a meteorological station. At 2514ma.s.l., it is the highest meteorological station in Slovenia, and has been in continuous operation since 1954. In this paper, the acquisition of three-dimensional data from archived, non-metric, panoramic, Horizont images is presented. The annual variations of Triglav glacier's area are given for the period 1976-2010, together with monthly snow variations for the years 1977 and 1998. Additionally, theoretical and empirical volumes and an empirical thickness reduction are computed. The changes to Triglav glacier are compared with the summarized meteorological data from the Kredarica meteorological station. In 1976 Triglav glacier covered an area of 15 ha; by 1992 this had shrunk to 4.3 ha, and it reached its minimum of 0.6 ha in 2003, as measured from Horizont images. Since then the glacier has been mainly conserved by the snow cover from previous winters.

Rener R.,Geodetic Institute of Slovenia
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2017

The safe and efficient mobility of persons with visual impairment may be secured with the development of new aids, based on new computer methods and technologies. The issue of mobility and accessibility is one of the central concerns in the development of »smart cities« and of accessible service for all inhabitants of urban areas. We will present an automated procedure for the production of tactile maps with the latest 3D printing technology for visually impaired persons. By employing a new method, which entailed the linking of geolocation data (digital maps, digital spatial images), new 3D tactile designing process and 3D print technology, we have reduced the costs and accelerated the production of tactile maps for visually impaired persons, and ensured the transportability of the products by converting them into a digital (STL) format. To exhibit the use of our new methodology, several production cases from Slovenia will be presented: the tactile map of the Slovene Ethnographic Museum, the tactile model of the Sečovlje Salina – the traditional production of salt, the tactile plate of the famous Schutze ceramic plate from 1886, the tactile map of the Library of the Union of the Blind and Partially Sighted of Slovenia, and the tactile map for orientation and mobility of the capital of Slovenia, Ljubljana. © Springer International Publishing AG 2017.

Trunk A.,Geodetic Institute of Slovenia | Stubelj I.,University of Primorska
Expert Systems with Applications | Year: 2013

The purpose of this paper is to discuss the effect of financial-economic crisis on the equity value of companies, as well as present the importance of fair and honest company valuations. The fundamental value of equity capital of a company is important for both management and external shareholders. The wide disparity between market and fundamental values can lead to high value adjustments, which reduces investors confidence in the capital market. This has had a negative impact on the operations of financial institutions, and individual as well as company investment; especially on developing financial markets during a financial-economic crisis. This research was designed to assess the equity value of Slovenian public limited companies based on the discounted free cash flows to equity and comparing it with market value of equity capital of companies before and during the financial-economic crisis. The fundamental value of equity capital of the selected companies (sample of 25) is calculated using a two-tiered model. The paired-sample t-tests method rejected the hypothesis that the fundamental value of equity capital of Slovenian public limited companies better reflects the market value of equity capital in today's times of financial-economic crisis (2011) than before the crisis (2006). However, we found that the market value of equity capital in relation to the fundamental value of equity capital of the selected companies was lower in 2011 than in 2006. Various models of the basic calculations are used in the model evaluation. This study shows the problem of company valuation on small and emerging capital markets which have a short history of data. © 2013 Elsevier Ltd. All rights reserved.

Bitenc M.,Geodetic Institute of Slovenia | Lindenbergh R.,Technical University of Delft | Khoshelham K.,Technical University of Delft | van Waarden A.P.,Data Management
Remote Sensing | Year: 2011

The Dutch coast is characterized by sandy beaches flanked by dunes. Understanding the morphology of the coast is essential for defense against flooding of the hinterland. Because most dramatic changes of the beach and the first dune row happen during storms, it is important to assess the state of the coast immediately after a storm. This is expensive and difficult to organize with Airborne Laser Scanning (ALS). Therefore, the performance of a Land-based Mobile Mapping System (LMMS) in mapping a stretch of sandy Dutch coast of 6 km near the municipality of Egmond is evaluated in this research. A test data set was obtained by provider Geomaat using the StreetMapper LMMS system. Both the relative quality of laser point heights and of a derived Digital Terrain model (DTM) are assessed. First, the height precision of laser points is assessed a priori by random error propagation, and a posteriori by calculating the height differences between close-by points. In the a priori case, the result is a theoretical laser point precision of around 5 cm. In the a posteriori approach it is shown that on a flat beach a relative precision of 3 mm is achieved, and that almost no internal biases exist. In the second analysis, a DTM with a grid size of 1 m is obtained using moving least squares. Each grid point height includes a quality description, which incorporates both measurement precision and terrain roughness. Although some problems remain with the scanning height of 2 m, which causes shadow-effect behind low dunes, it is concluded that a laser LMMS enables the acquisition of a high quality DTM product, which is available within two days. © 2011 by the authors.

Berk S.,Geodetic Institute of Slovenia | Komadina Z.,Surveying and Mapping Authority of the Republic of Slovenia
Survey Review | Year: 2013

The present paper presents a geodetic datum transformation between the old and new national coordinate reference systems of Slovenia. The basis for transformation is a set of about 2000 points coordinated in both systems. Virtual tie points are used, which form a regular triangular network covering the entire country. In order to enable extrapolation, the network was expanded, thereby reducing its density. Coordinate shifts between both coordinate systems were determined using best-fit transformation in the immediate neighbourhood of each virtual tie point. Weights assigned to these points depend upon their density and distance from the virtual tie point. The results prove significant advantages of the proposed model: high accuracy, minimisation of distortions, continuity and reversibility of transformation. Therefore, the model has been chosen for transformation of all spatial databases which continuously cover the entire territory of the country and require transformation accuracy of better than one metre. © 2013 Survey Review Ltd.

Physical 3D maps have a fine history in cartography, but they require the highest level of craftsmanship and artistic talent from a cartographer. However, 3D printing technology can simplify production of 3D maps. This technology saves time and enables multiple reproduction of the same map, without painstaking manual labour. Nonetheless, to produce a high-quality 3D map, cartographers must use well-established cartographic principles and techniques. This paper describes the creation of a physical 3D map of the Planica Nordic Center. The main purpose of the map is to promote and clarify future development of the sports centre and to show its final infrastructure and landscaping. This paper describes the data, technology, and design decisions used in making the map. It also discusses the cartographic principles and techniques used in the making of the map, and the lessons learned. © University of Toronto Press.

Triglav-Cekada M.,Geodetic Institute of Slovenia | Radovan D.,Geodetic Institute of Slovenia
Natural Hazards and Earth System Sciences | Year: 2013

Volunteered geographical information represents a promising field in the monitoring and mapping of natural disasters. The contributors of volunteered geographical information have the advantage that they are at the location of the natural disaster at exactly the time when the disaster happened. Therefore, they can provide the most complete account of the extent of the damage. This is not always possible when applying photogrammetric or remote-sensing methods, as prior to the data acquisition an order to carry out the measurements has to be made. On 5 and 6 November 2012 almost half of Slovenia was badly affected by floods. The gathering of volunteered geographical information in the form of images and videos of these floods is presented. Two strategies were used: (1) a public call for volunteered contributions and (2) a web search for useful images and their authors. The authorship of these images was verified with every contributor. In total, 15 contributors provided 102 terrestrial and aerial images and one aerial video, with 45 % classified as potentially useful. For actual flood mapping 22 images and 12 sequences from video were used. With the help of the volunteered images 12% of the most severely affected river sections were mapped. Altogether, 1195.3 ha of flooded areas outside of the usual river beds along a total river length of 48 km were mapped. The results are compared with those from satellite mapping of the same floods, which successfully covered 18% of the most affected river sections. © Author(s) 2013.

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