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1

The assessment of elevation data consistency : A case study using the ALS and georeference database in the City of Kraków

Piech Izabela, Policht-Latawiec Agnieszka, Lackóová Lenka, Inglot Paulina

Journal of Water and Land Development

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2023

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no. 59

135--144

EN

The integration of geodetic and photogrammetric data has become a new tool that has expanded the existing measurement capabilities, as well as it found its application outside the geodetic sector. As a result, over the past decades, the process of topographic data acquisition has caused cartographic industry to move from classical surveying methods to passive and active detection methods. The introduction of remote sensing technology has not only improved the speed of data acquisition but has also provided elevation data for areas that are difficult to access and survey. The aim of the work is to analyse consistency of elevation data from the Georeference Database of Topographic Objects (Pol. Baza danych obiektów topograficznych - BDOT500) with data from airborne laser scanning (ALS) for selected 15 research areas located in the City of Kraków. The main findings reveal discrepancies between elevation data sources, potentially affecting the accuracy of various applications, such as flood risk assessment, urban planning, and environmental management. The research gap identified in the study might stem from the lack of comprehensive investigations into the consistency and accuracy of elevation data across different databases and technologies in urban areas. This gap highlights the need for a thorough examination of the reliability of various data sources and methods of urban planning, disaster management, and environmental analysis. The integration of diverse databases and technologies, like ALS and geodetic measurements, in various applications introduces potential discrepancies that can significantly impact decision-making and outcomes.

2

Effects of non-classical boundary conditions on the free vibration response of a cantilever Euler-Bernoulli beams

Afras Abderrachid, El Ghoulbzouri Abdelouafi

Diagnostyka

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2023

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Vol. 24, No. 1

art. no. 2023107

EN

In this article, the problem of the free vibration behavior of a cantilever Euler-Bernoulli beam with various non-classical boundary conditions, such as rotational, translational spring, and attached mass is investigated. For describing the differential equation of the system. An analytical procedure is proposed firstly, and a numerical method based on the differential transform method DTM is developed in order to validate the obtained results. A parametric study for various degenerate cases is presented with the aim to analyze the influence of rotational stiffness, vertical stiffness, and mass ratio on the free vibration response of the beam, particularly on its modal characteristics. The results show that the non-classical boundary conditions significantly affect the natural frequency and mode shapes of the studied beam system in comparison to the case of a classical boundary conditions such as Simply supported, clamped-clamped, etc. The comparison between the obtained results based on the proposed analytical solution and numerical scheme, and those available in the literature shows an excellent agreement.

3

Litologiczny wskaźnik przemieszczeń materiału skalnego jako element oceny podatności stoków na osuwanie

Wódka Marcin

Przegląd Geologiczny

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2022

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Vol. 70, nr 9

695--700

EN

The use of multi-temporal LIDAR data in the study of landslides gives many possibilities. The increasing-over-time availability of ALS data encouraged research on development of landslides using Differential Digital Terrain Models. An important passive factor that determines the development of landslides (especially in the Carpathians) is lithology. The author propose a new lithological displacement index, that dscribes the volume of displaced ground (m3 ) per area of 1 m2 of a given lithological unit. The example of the test area of Rożnowskie Lake has shown that lithological displacement index can assess the landslide susceptibility, which is variable and depends on the amount of rainfall. During periods of heavy rainfall, large volumes of displaced rock masses were recorded in the thick-bedded formations. In dry periods, the trend is reversed.

4

Charakterystyka osuwisk powstałych na hałdach po górnictwie rud żelaza w rejonie częstochowskim

Górka Konrad, Piotrowski Andrzej

Przegląd Geologiczny

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2022

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Vol. 70, nr 9

682--694

EN

For about 600 years Middle Jurassic iron ores had been mined in the Częstochowa region. This process created many forms, among which mining and processing waste dumps are the best visible in this area. After the mining process had stopped, mass movements occured in the surface of the dumps. The paper presents specificity of landslides developed in dumps in the Częstochowa region, intensity of this phenomenon and landslides activity. Mass movements are present in each dump higher than 40m and broader than 300 m. The large stand highest dump slopes are all covered by a vast landslide zones, where rotational slides and complex slides dominates. Despite the fact that exploration of iron ores had ended about 40 years ago, a large number of dump landslides are still active or periodically active. Some of these signs of activity can be seen on Differential Digital Model (DDM).

5

Badanie lokalnej zgodności ogólnodostępnych danych LiDAR z danymi bazy BDOT500 z zastosowaniem technik GIS

Maciąg Klaudia, Leń Przemysław, Maciąg Michał

Przegląd Geodezyjny

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2022

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R. 94, nr 2

13--16

PL

Światowy postęp technologiczny w dziedzinie teledetekcyjnych metod modelowania powierzchni Ziemi stopniowo prowadzi do uzyskania dokładności porównywalnych z wynikami naziemnych pomiarów geodezyjnych. Ogólnodostępne dane LiDAR pomimo ograniczonej precyzji mogą zostać wykorzystane m.in. w celu wspomagania i kontroli procesu pozyskiwania danych wysokościowych. W niniejszym opracowaniu przedstawiono uproszczoną metodę weryfikacji zgodności danych LiDAR z geodezyjnymi danymi wysokościowymi bazy BDOT500. Przeprowadzone doświadczenie umożliwiło określenie potencjalnego zakresu zastosowania danych teledetekcyjnych. W oparciu o uzyskane wyniki opracowano koncepcję modyfikacji struktury bazy BDOT500, umożliwiającej warunkowe uzupełnienie mapy numerycznej na określonych obszarach bez konieczności wykonywania prac terenowych.

EN

The worldwide technological progress in the field of remote sensing methods of the Earth surface modelling, is gradually resulting in receiving accuracies comparable with the ground-based surveying results. The open LiDAR data, despite the constrained accuracy, may be implemented i.a. for supporting and monitoring the process of the elevation data acquirement. In this paper, a simplified method of verifying the agreement between the LiDAR data and the geodetic elevation data from BDOT500 database has been reported. The experiment conducted enabled to determine the potential range of the remote sensing data implementation. According to the results obtained, a concept of BDOT500 database structure modification for conditional supplementation of the numerical map without the fieldwork, has been formulated.

6

Analysis of algorithms for automatic classification of photogrammetric point clouds to build a digital terrain model in a shoreline area

Łącka Małgorzata

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2021

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nr 68 (140)

108--118

EN

Unmanned aerial vehicles (UAVs) allow relatively cheap and fast acquisition of high-resolution data for small areas, making it possible to produce not only an orthophoto, understood as a two-dimensional product, but also a three-dimensional point cloud, which is the basis for obtaining a digital terrain model (DTM). The use of high-resolution image and elevation data may allow accurate shoreline delineation in areas where such measurement is not possible with other methods and further use of these data, e.g. for the production of electronic navigation charts. The accuracy of the final product, the DTM, is significantly affected by the photogrammetric classification process of the point cloud and the correct separation of the ground class. The aim of this study was to assess the effectiveness of the algorithms used to classify ground in photogrammetric point clouds and obtain correct DTMs. Three algorithms were tested: Adaptive Triangulated Irregular Network, Progressive Triangulated Irregular Network, and Multiscale Curvature Classification. The study involved two test areas covering natural shorelines. Images acquired with a UAV on the X8 system and a Sony alpha camera with a mounted 15 mm wide-angle lens were used as data for the research experiment. Accuracy analysis of the developed models was performed using check points acquired by the GNSS-RTK method.

7

Zastosowanie bezzałogowych statków powietrznych w dokumentowaniu geologiczno-inżynierskim

Piechota Arkadiusz, Sobótka Przemysław

Przegląd Geologiczny

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2021

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Vol. 69, nr 12

861--866

EN

The article presents the possibilities of using unmanned aerial vehicles (UAV) in engineering geology. The first part compares the method of obtaining products from UAV with airborne laser scanning, showing its limitations and advantages. Then, examples of using the products made from photos obtained from UA V raids (digital surface model - DSM, digital terrain model - DTM and orthophotomosaic) were introduced. The examples are assigned to the individual phases of engineering geology documentation (collecting available information about the site, designing research, performing research and presenting research results). The last part presents an analysis of the accuracy of an exemplary model created from a UAV raid based on control points measured using the GNSS-RTN method. The result of the analysis was the confirmation of the possibility of obtaining information about the area from the DSM, DTM and orthophotomosaic with high accuracy comparable to classic land surveying methods.

8

Review of DTM derivatives most used in digital soil mapping

Radło-Kulisiewicz Małgorzata

Geomatics, Landmanagement and Landscape

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2021

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no. 2

87--99

EN

Digital Soil Mapping (DSM) is a subdiscipline of pedology, where soil cover is modelled through use of spatial – temporal relations between environmental covariates and soil. The process of quantitative terrain description used in DSM is called terrain parametrization, where terrain attributes (morphometric factors, Digital Terrain Model derivatives) are the most used predicators. Terrain parameterisation was used as a tool in the hydrological survey workshop long before computers had been in use. With the development of digitisation, it also began to be used to determine selected soil attributes, which was greatly facilitated by GIS applications. A significant breakthrough in the importance of terrain attributes in the creation of soil maps and models took place with the formalisation of rules for digital soil mapping. Literature describes over 50 indices, although only a few of them are commonly applied. This applies to single soil attributes as well as more advanced implementations in more sophisticated models such as artificial intelligence algorithms. The aim of the following article is to present the main components of DSM and to describe characteristics of the most commonly derivatives of DTM applied there, also refers to several examples of the use of terrain parameters in the context of DSM in terms of the resolution of the elevation model used.

9

Trudności w wyznaczaniu osuwisk na obszarach historycznych i zurbanizowanych na przykładzie Twierdzy Przemyśl

Rycio Edyta

Przegląd Geologiczny

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2020

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Vol. 68, nr 12

902--914

EN

The Przemyśl Fortress is a huge complex of defensive objects from the turn of the 19th and 20th centuries. Various types of objects, ruins and remains of the fortress and signs of fights have been preserved to different extents in the area to this day. They constitute a huge problem when determining landslides. The greatest difficulties are caused by vegetation-covered ruins of forts, trenches, remnants of ramparts and defense ditches, and signs of fights preserved in places. Such residues can be interpreted as a landslide or a part of it, especially if they occur in a neighbourhood or inside a landslide. The problem then arises of clearly identifying the boundaries of the landslide and the correct identification of its internal forms, e.g. a devastated trench around the fort can be marked as a landslide. Similar difficulties are provided by numerous inactive quarries, excavations, clay pits, e.g. a closed limestone open-pit mine from the 19th century, located in Kruhel Wielki. Elements of the old mine are deceptively reminiscent of intra-fieldforms and they are difficult to separate from the real colluvial forms of the neighbouring landslide. Difficulties in determining landslides arise not only from the history of this region and its geological structure, but also from the degree of urbanization of the area. Strong anthropopression blurs the natural morphology of the slopes, and the limited availability of the area makes cartographic work difficult. It is difficult to distinguish between natural and artificial forms in such areas. Good examples are landslides on the ski slope, on the municipal cemetery, in the castle park and in the area of military areas, housing estates and allotments.

10

Opracowanie numerycznego modelu terenu Poznańskiego Węzła Wodnego na potrzeby dwuwymiarowego modelu przepływu

Pręcikowska Magdalena, Laks Ireneusz

Przegląd Budowlany

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2020

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R. 91, nr 4

40--45

PL

W pracy opisano proces opracowania numerycznego modelu terenu (NMT) Poznańskiego Węzła Wodnego w celu wygenerowania zestawu danych dla dwuwymiarowego hydrodynamicznego modelu przepływu poznańskiego odcinka rzeki Warty. Zakres prac obejmował pozyskanie podkładów geodezyjnych numerycznego modelu terenu bazującego na lotniczym skaningu laserowym (LIDAR), wykonaniu geodezyjnych pomiarów wysokościowych w celu weryfikacji poprawności NMT, wykonaniu pomiarów batymetrycznych dna, generacji przekrojów pośrednich koryta rzeki, scaleniu informacji o batymetrii z NMT wykorzystujących narzędzia GIS (Geographic Information System), generacji siatki metody elementów skończonych (MES) oraz utworzeniu pliku danych w standardzie akceptowalnym przez dwuwymiarowy system modelowania przepływów nieustalonych RISMO2D. W trakcie badań wykorzystano nowoczesną aparaturę pomiarową: ultradźwiękową sondę ADCP StreamPro umożliwiającą pomiar zarówno rozkładu prędkości w przekroju kontrolnym, jak i batymetrii cieku, geodezyjnego sprzętu GPS Sokkia-11 umożliwiającego szybki pomiar trzech współrzędnych wybranego w terenie punktu. Analiza i post-processing danych pomiarowych wymagała wykorzystania narzędzi klasy GIS (wybrano system QGIS) oraz oprogramowania specjalistycznego.

EN

The paper describes the process of developing a digital elewation model (DEM) of the Poznań Waterway System in order to generate a data set for a two-dimensional hydrodynamic flow model of the Poznań section of the Warta river. The scope of work included the acquisition of a digital elevation model based on aerial laser scanning (LIDAR), geodetic height measurements to verify the correctness of DEM, bathymetric measurements, generation of intermediate sections of the river bed, merging information about bathymetry with DEM using GIS (Geographic Information System), generation of the finite element method mesh (FEM) and creation of a data file in a standard acceptable by the two-dimensional transient flow modeling system RISMO2D. During the work, modern measuring equipment was used: an ultrasonic ADCP StreamPro probe enabling measurement of both speed distribution in the control section and water bathymetry, Sokkia-11 geodetic equipment enabling quick measurement of three coordinates of a point in the area. The analysis and post-processing of measurement data required the use of GIS class tools (QGIS system selected) and specialized software.

11

Determining Density of Regular Grid for Creating DTM Using Bicubic Spline Interpolation

Burak Konstantyn, Kovtun Vitalii, Levytskyi Roman, Makoviichuk Mykola

Geomatics and Environmental Engineering

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2019

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Vol. 13, no. 2

5--18

EN

The article present the accuracy of DTM reproduction created by authors program of bicubic spline interpolation on the example of different categories of relief complexity. Correlations are established between the size of regular grid, category of relief complexity and a mean-square error of height finding. The graph is drawn showing the dependence of accuracy of point height finding from DTM, the size of regular grid and category of relief complexity.

PL

Za pomocą stworzonego przez autorów programu do interpolacji splajnami dwusześciennymi (BSI, bicubic spline interpolation) zbadano dokładność odtworzenia terenu w numerycznym modelu terenu (NMT). Analizowano kategorie terenu o różnym stopniu skomplikowania morfologii. Ustalono korelacje między rozmiarem regularnej sieci, kategorią skomplikowania rzeźby powierzchni terenu i średniokwadratowym błędem ustalania wysokości punktu. Wykonano wykres zależności dokładności wyznaczenia wysokości punktów z wykrzystaniem NMT od kroku regularnej siatki i stopnia skomplikowania morfologii terenu.

12

Porównanie oprogramowania do przetwarzania danych LiDAR w zakresie generowania NMT i NMPT

Bielecki A.

Teledetekcja Środowiska

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2018

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T. 58

5--11

PL

Dane LiDAR dostarczają wielu informacji o terenie jednak wymagają bardzo czasochłonnych procesów obróbki oraz odpowiednich zasobów sprzętowych. W trakcie analiz przestrzennych bazujących na dużych zestawach danych napotkać można wiele problemów natury technicznej. W artykule podjęto próbę konwersji chmury punktów do modelu rastrowego NMT oraz NMPT. Szukając najlepszego rozwiązania wykorzystano 7 różnych programów dostępnych na licencji studenckiej, open-source oraz w wersji próbnej. Każdy program jednak znacząco różni się pod względem ingerencji użytkownika, możliwości analitycznych, możliwości automatyzacji czy też radzenia sobie z dużymi zestawami plików, stąd też wybór odpowiedniego oprogramowania jest bardzo trudny.

EN

LiDAR data provides a lot of information about terrain, but they need very time consuming processes of generating other products and a good quality of hardware. During spatial analyses based on big sets of data one can meet many technical problems. In the article it was made an attempt to build a DTM and a DSM raster models based on point cloud. Looking for the best solution 7 different software has been used available on educational, open-source of trial license. Each software is different regarding the user integration, analytics possibilities, abilities to automate the processes and management of working with big size data. That is why the choose between the best software is so hard.

13

Investigation of a Jeffery-Hamel flow between two rectangular inclined smooth walls using the differential Transform Method

Patel N. D., Meher R.

Journal of Applied Mathematics and Computational Mechanics

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2018

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Vol. 17, nr 4

47--57

EN

In this article, the Differential Transform Method (DTM) is applied to derive a semi-analytic solution for the non-linear MHD (Magneto Hydro Dynamics) Jeffery-Hamel flow between rectangular inclined smooth planes. A non-linear ordinary differential equation of order four is obtained from Navier-Stokes equations using similar transformation. A comparison between DTM, PM (Perturbation Method) and numerical solution is shown here to validate the obtained results with its convergence analysis for different values of m and a Reynolds number in divergent channels.

14

Możliwości generowania precyzyjnego NMT na podstawie chmury punktów z projektu ISOK

Biszof A., Oberski T.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2018

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vol. 30

95--106

PL

Procesy tworzenia oraz wizualizacji NMT na podstawie danych z lotniczego skaningu laserowego stają się coraz powszechniejsze. Jakość NMT jest uzależniona od wielu czynników. W pracy poddano analizie proces tworzenia NMT w aspekcie zróżnicowania ukształtowania terenu, wielkości siatki GRID oraz metod interpolacji na podstawie danych pozyskanych z projektu ISOK dla fragmentu (1km2) miasta Koszalin. Wykorzystano interpolacje deterministyczne oraz stochastyczną do uzyskania modeli o rozdzielczościach 0.1 m, 0.25 m oraz 0.5 m. Porównano ponadto otrzymane modele ze standardowym NMT pozyskanym z ISOK. Największy wpływ na jakość NMT zbudowanego na podstawie danych LIDAR ma zróżnicowanie terenu. Ponadto w zależności od przeznaczenia modelu sprawdzono, czy zmiana wielkości oczka tworzonego modelu GRID ma wpływ na jakość NMT zwłaszcza w kontekście odwzorowania form morfologicznych rzeźby.

EN

Creating and visualizing DTM based on data from airborne laser scanning become a common practice. Quality of DTM depends on many factors. The paper analyzes the process of creating a DTM in terms of diversity of terrain, the size of grid (the cell size) and methods of interpolation, based on data obtained from the project ISOK for a part (1km2) of the city of Koszalin. Deterministic and stochastic interpolations are used for cellsizes of 0.1 m, 0.25 m and 0.5 m. Moreover, the models were compared with DTM obtained from the ISOK. Diversity of terrain has the biggest impact on the quality of DTM based on LIDAR data. Furthermore, depending on the application of the model, it has been checked if reducing the cellsize of the created model GRID affects the quality of the DTM, especially in the context of mapping morhological forms.

15

Zapis typu ruchu osuwiska w rzeźbie terenu i jego obraz na wysokorozdzielczych numerycznych modelach terenu (NMT) na przykładzie wybranych osuwisk ze wschodniej części Beskidu Niskiego (Karpaty zewnętrzne, Polska)

Kaczorowski J.

Przegląd Geologiczny

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2017

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Vol. 65, nr 1

44--2

EN

Landslides are very common features in the Polish Outer Carpathians. In the classical cartography, landslides are recognized based on characteristic land relief: main and side scarps, toe, minor scarps, transverse ridges, recesses and cracks. Formerly, landslide mapping was carried out in the field, preceded by interpretation of topographic maps and aerial photographs. Nowadays, we use spatial data from airborne laser scanning (ALS). Spatial data reprocessing permits to achieve a high-resolution (pixel 1*1 m or more precise) digital terrain model (DTM). Exploration of land relief in search for landslides has become simpler and more accurate. DTM interpretation allows delimiting the boundaries of landslides and elements of their relief. By analysing groups oflandforms it is possible to determine the type of colluvium movement. In the eastern part of the Low Beskid Mts., four types of landslides predominate: rotational slides, translational slides, flows, and complex movements. Types of landslides are usually very well visible on the DTM. Information about types of mass movements can be useful during modelling further landslide activity and designing instrumental identification works and possibility ofstabilization.

16

Lotniczy skaning laserowy (LiDAR-ALS) jako źródło danych do obliczeń stateczności skarp na terenach zadrzewionych i zakrzewionych

Piechota A.

Przegląd Geologiczny

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2017

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Vol. 65, nr 10/2

811--816

EN

The paper discusses the problem of quick acquire height data for calculation of escarpment stability. In past the slope of profile was obtainedfrom classical land survey methods (like Total Station, GNSS, etc.), carto- metric measurement on maps or measurements based on a Digital Terrain Modelfrom aerial photography. Now we have a new method that is Airborne Laser Scanning (LiDAR-ALS). In 2011-2014 almost all country was measured in this method. The declared accuracy of height measurement on the durable surfaces is about 0.10-0.15 m. Author compared this method with classical method Global Navigation Satellite System - Real Time Network (GNSS-RTN) on two wooded and bushy areas. The comparison was based on the measurement characteristic points on the profiles and acquisition of height data from LiDAR-ALS data. Data in this method were obtained in two ways: from point cloud and from DTM createdfrom this point cloud. In the next step, height differences were calculated and these data were subjected to basic statistical calculations. The result of the study was a mean error of height data from LiDAR-ALS and conclusions about its usefulness in acquire height data for calculation of escarpment stability.

17

Application of reconstruction of variational iteration method on the laminar flow in a porous cylinder with regressing walls

Azimi M., Hedesh A. M., Karimian S.

Mechanics and Mechanical Engineering

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2017

|

Vol. 21, nr 2

379--387

EN

A study of an incompressible two-dimensional flow in a channel with one porous wall is presented in this research. As usual, the cylindrical propellant grain of a solid rocket motor is modeled as a long tube with one end closed at the headwall, while the other remains open. The governing continuity and momentum equations together with the associated boundary conditions are first reduced to a set of self similar non-linear coupled ordinary differential equations using similarity transformations. Then we solved the ordinary differential equation by RVIM and the numerical method.

18

Stosowanie wybranych metod generowania regularnych modeli terenu z lotniczego skaningu laserowego do badań środowiskowych

Rozpondek K., Wancisiewicz K.

Inżynieria i Ochrona Środowiska

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2017

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T. 20, nr 1

83--95

EN

The accuracy of models representing the shape of the land surface is important in environmental studies. Accurate model can be used to detect even small changes in the landform and landuse, as well as to develop a spatial model of water and soil pollution. Due to the fact that environmental studies are carried out on diversified areas in terms of landuse, this study indicated the appropriate methods for generating Digital Terrain Model (DTM) and Digital Surface Model (DSM). Both of them can be used in processes and analyzes research. Those analyzes mainly take into account the formation of the Earth’s surface in the context of hydrological, geomorphological and biological modeling. The example of practical use of hydrological modeling is a ISOK project, which goal is to reduce the danger and minimize losses caused by the floods. The main aim of this study was to select the appropriate method of generating regular models from airborne laser scanning. The data on which analysis was performed, were obtained for the area of Cracow city within the project ISOK. To achieve this goal, four methods available in ArcGIS, were selected: nearest neighbour, inverse distance weighted, triangulation with linear interpolation and triangulation with natural neighbour interpolation. Additionally several different sizes of the cell of regular model were selected: 0.125, 0.25, 0.5, 1, 2.5, 5 m. Each generated model has been studied in terms of a accuracy (Gaussian statistical model was used). Firstly the analysis was made for digital terrain model and digital surface model for one archive module of point cloud. For this stage, 48 models were generated. After that, the area of analysis was expanded. Because of similar results obtained by both triangulations methods in the first stage, only the method of triangulation with linear interpolation was studied. In the second stage of research, 54 models were generated for other archive modules of point cloud. The results of the two stages were compatible. It has been noticed that the nearest neighbour method is the most accurate for generating Digital Surface Models.

PL

Dokładność modeli reprezentujących ukształtowanie powierzchni terenu jest istotna w badaniach środowiska. Poprawnie wykonane modele mogą być wykorzystane do wykrywania nawet niewielkich zmian w ukształtowaniu i zagospodarowaniu terenu, a także do opracowania modelu przestrzennego zanieczyszczeń wód oraz gleby. Ze względu na to, że badania nad środowiskiem prowadzone są na obszarach zróżnicowanych pod kątem zagospodarowania terenu, w niniejszej pracy wskazano odpowiednie metody generowania Numerycznych Modeli Terenu (NMT) i Numerycznych Modeli Pokrycia Terenu (NMPT). Dane, na których wykonano analizy, były pozyskane dla obszaru miasta Kraków w ramach projektu ISOK. Aby osiągnąć założony cel, wybrano cztery metody dostępne w oprogramowaniu ArcGIS: najbliższego sąsiada, wagowanej odwrotnej odległości, triangulacji z metodą interpolacji liniowej i naturalnego sąsiada. Wybrano także kilka różnych rozmiarów oczek siatki modelu (0,125 m, 0,25 m, 0,5 m, 1 m, 2,5 m, 5 m). Każdy wykonany model został poddany analizom dokładnościowym - zastosowano model Gaussa. W pierwszym etapie badań wygenerowano 48 modeli dla arkusza chmury punktów zawierającego zróżnicowane klasy pokrycia terenu. W drugim wykonano dodatkowo 54 modele dla pozostałych badanych arkuszy. Wyniki obu etapów prac były ze sobą zgodne. Stwierdzono, że metoda najbliższego sąsiada jest najbardziej dokładna w przypadku generowania modeli NMPT. Natomiast w przypadku NMT badania nie wskazały jednoznacznie najlepszej metody interpolacji danych wysokościowych terenu.

19

Analysis of the distribution and density of measurement points in terms of terrain modelling

Gradka R.

Geomatics, Landmanagement and Landscape

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2017

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no. 3

35--45

EN

For the implementation of direct measurements, proper understanding of the existing relationships and spatial variability, and at later stages, for obtaining reliable results of geostatistical analysis, adequate planning network measurement and correct placement of, and/or the evaluation of the number of measurement points in the measurement network are not the only necessary conditions. Another key prerequisite is choosing the right model for creating a DTM, which depends on the shape of the terrain. Correct spatial sampling should provide much information on the spatial distribution of the studied variable in an area, at minimal cost and with minimal effort. Faithful reproduction of the land surface that reflects any of the characteristics of the environment is not possible through DTM, due to a number of restrictions, manifesting themselves in the form and size of the data set; due to time and economic constraints; and also because the full complexity of the terrain’s surface cannot be measured or expressed. The present work undertakes to analyse the density and distribution of measuring points on four areas that have specific characteristics in common, yet they remain different in terms of surfaces, height differences, as well as their complexity. After selecting the research areas, these were designed and laid out in a grid with the shape of rectangles that were similar in structure to the GRID model. The data were analysed using geostatistical interpolation by ordinary kriging, in order to conduct a proper analysis of the distribution and density of the measuring points, to calculate the surface properties of a particular point, and in order to attempt to reduce the workload and cost factor.

20

Accuracy assessment of TanDEM-X IDEM using airborne LiDAR on the area of Poland

Woroszkiewicz M., Ewiak I., Lulkowska P.

Geodesy and Cartography

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2017

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Vol. 66, no. 1

137--148

EN

The TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X) mission launched in 2010 is another programme – after the Shuttle Radar Topography Mission (SRTM) in 2000 – that uses space-borne radar interferometry to build a global digital surface model. This article presents the accuracy assessment of the TanDEM-X intermediate Digital Elevation Model (IDEM) provided by the German Aerospace Center (DLR) under the project “Accuracy assessment of a Digital Elevation Model based on TanDEM-X data” for the southwestern territory of Poland. The study area included: open terrain, urban terrain and forested terrain. Based on a set of 17,498 reference points acquired by airborne laser scanning, the mean errors of average heights and standard deviations were calculated for areas with a terrain slope below 2 degrees, between 2 and 6 degrees and above 6 degrees. The absolute accuracy of the IDEM data for the analysed area, expressed as a root mean square error (Total RMSE), was 0.77 m.