The Generalization of the Digital Terrain Model Based on the TIN Abstract This diploma thesis deals with the up to now way and the possibilities of the digital terrain model generalization based on the TIN (the triangulate irregular network). New suitable way of the generalization of the digital terrain model procured from laser scanning data is proposed on the base of the existing generalization methods designated for digital models. Laser scanning data is characterized by a high areal density so the basic requirement is computing speed, maintaining the terrain features, such as a ridge, valley, steep hill, saddle, depression … and so on. The proposed algorithm is compared with the results of suggested algorithms and results from the generalization by the geographic software, such as Atlas DMT and ArcGIS.

Techniques for procedural generation of the graphics content have seen widespread use in multimedia over the past thirty years. It is still an active area of research with many applications in 3D modeling software, video games, and films. This thesis focuses on algorithmic generation of virtual terrains in real-time and their real-time visualization. We provide an overview of available approaches and present an extendable library for procedural terrain synthesis. Powered by TCPDF (www.tcpdf.org)

The aim of this work is to design automatic detection of spot heights from airborne laser scanning data and its generalization. The first part is about the idea of spot height: the importance of spot heights for altimetry representation on maps and suggestions concerning the scatter of spot heights on maps. In the following part, different approaches for terrain critical points extraction (peaks, depressions, passes) from digital terrain models are described as suitable places for spot heights location. Further, we introduce a description of geomorphological characteristics of these points by which is possible to identify its significance and generalize them. In accordance to analysis of Základní mapa ČR and recommendation for spot heights location described in literature we designed own method of automatic generation and generalization spot heights from digital terrain models. This method were implemented and there is a description of the test data and results on the real data DMR 5G of the algorithm in the end of the work. Powered by TCPDF (www.tcpdf.org)

Snow accumulation patterns can be highly variable depending on terrain and wind. Knowledge of spatial variability of snow accumulation is of high relevance for mass balance modelling. By not incorporating the variability in snow cover, the estimation in mass fluxes and the surface melt are incorrectly presented, affecting the eventual estimation of for instance contribution to sea level rise. Additionally, knowledge of snow accumulation variability is essential for assessing the reliability of point-wise mass balance measurements. Using ground penetrating radar (GPR), the spatial variability of snow can be mapped with both a great spatial and temporal resolution. GPR enables tracing of summer surface melt layers, resulting in a 2D reconstruction of past snow accumulation and associated variability. GPR measurements have been done on Svalbard, during 2012, 2013 and 2014. Based on the selected 2009 summer surface in the GPR measurements, accumulation rates were estimated between 2009-2012; 2009-2013 and 2009-2014. In addition, several terrain parameters are computed by combining DEM calculations with wind direction, resulting in a sheltering index, slope and curvature. We explore relationships between the found accumulation pattern and the terrain parameters with varying wind directions. Correlations between terrain and accumulation depend on the selected wind angle, which appears to change with elevation. The results suggest that localized wind patterns prevail on the glacier and shape the snow cover. Katabatic winds form at low elevations on the glacier and are oriented in the glacier direction of approximately 20 degrees. At intermediate elevation, winds from the east-southeast regulate the accumulation pattern. On the upper parts of the glacier, the terrain is more exposed and winds from large-scale atmospheric circulation, at 240 degrees, become more important in formation of the snow accumulation pattern. Correlations are overall high, indicating a strong influence of terrain features on the accumulation distribution. No distinction can be made between the different terrain parameters and accumulation, all returning similar correlations with accumulation except for curvature, which overall returns slightly lower correlations. In addition, the results found great spatial variability in snow accumulation, underlining the importance of incorporating snow accumulation variability in glacier mass balance models. / Snow accumulation patterns can be highly variable depending on terrain and wind. Knowledge of spatialvariability of snow accumulation is of high relevance for mass balance modelling. By not incorporating the variability in snow cover, the estimation in mass fluxes and the surface melt are incorrectlypresented, affecting the eventual estimation of for instance contribution to sea level rise. Additionally,knowledge of snow accumulation variability is essential for assessing the reliability of point-wise mass balance measurements.Using ground penetrating radar (GPR), the spatial variability of snow can be mapped with both agreat spatial and temporal resolution. GPR enables tracing of summer surface melt layers, resulting in a 2D reconstruction of past snow accumulation and associated variability. GPR measurements have been done on Svalbard, during 2012, 2013 and 2014. Based on the selected 2009 summer surface in the GPR measurements, accumulation rates were estimated between 2009-2012; 2009-2013 and 2009-2014. In addition, several terrain parameters are computed by combining DEM calculations with wind direction, resulting in a sheltering index, slope and curvature. We explore relationships between the found accumulation pattern and the terrain parameters with varying wind directions.Correlations between terrain and accumulation depend on the selected wind angle, which appears to change with elevation. The results suggest that localized wind patterns prevail on the glacier and shape the snow cover. Katabatic winds form at low elevations on the glacier and are oriented in the glacier direction of approximately 20 degrees. At intermediate elevation, winds from the east-southeast regulate the accumulation pattern. On the upper parts of the glacier, the terrain is more exposed and winds from large-scale atmospheric circulation, at 240 degrees, become more important in formation of the snow accumulation pattern. Correlations are overall high, indicating a strong influence of terrain features on the accumulation distribution. No distinction can be made between the different terrain parameters and accumulation, all returning similar correlations with accumulation except for curvature, which overall returns slightly lower correlations. In addition, the results found great spatial variability in snowaccumulation, underlinin

The aim of this work is to examine the application Topocoding API and Google Maps API. Analyze system requirements to define the coverage of wireless connectivity to allow the ISP so as to allow the ISP to file AP and customers, as well as exploring the possibilities of joining the AP ISP and view coverage maps. Further, this application design, implement and test.

Background. Being able to modify virtual environments can create immersive experiences for video-game players. Storing data as volumetric scalar fields allows for highly modifiable 3D environments that can be converted into GPU-friendly triangles with isosurface algorithms. Using scalar fields and isosurface algorithms can be more computationally expensive and require more data than the more commonly used polygonal models. Objectives. The aim of this thesis is to explore solutions to modifying real-time 3D environments with isosurface algorithms. This will be done in two parts. First in terms of observing how modern games deal with storing scalar fields, researching which isosurface algorithms are being used and how they are being used in games. The second part is to create an application and limit the data storage required while still running at a real-time speed. Methods. There are two methods to achieve the aim. The first is to research and see which data structures and isosurface algorithms are being used in modern games and how they are utilized. The second method will be done by implementation. The implementation will use the GPU through compute shaders and use marching cubes as isosurface algorithm. It will utilize Christopher Dyken’s Histogram Pyramids for stream compaction. Two different versions will be implemented that differ in terms of what data types will be used for storage. The first using the data type char and the second int. Between these two versions, the runtime speed will be measured and compared on two different hardware configurations. Results. Finding good data on what algorithms games use is difficult. Modern games are using scalar fields in many different ways: Some allow almost complete modification of terrain, others only use it for a 3D environment. For data storage, octrees and chunks are two common ways to store the fields. Dual Contouring appears to be the primary isosurface algorithm being used based on the researched games. The results of the implementation were very fast and usable in real time environments for destruction of terrain on a large scale. The less storage intensive variation of this implementation(char) gave faster results on modern hardware but the opposite(int) was true on older hardware. Conclusions. Modifying scalar field terrain is done at a very large scale in modern games. The choice of using Dual Contouring or Marching Cubes depends on the use-case. For areas where sharp features can be important Dual Contouring is the preferred choice. Likely for these reasons Dual Contouring was found to be a popular choice in the studied games. For other areas, like many types of terrain, Marching Cubes is very fast, as can be seen in the implementation. By using the char version of the implementation, interacting with the environment in real-time is possible at high frame-rates.

Video game characters must almost always be able to travel from point A to point B and this task can be solved in various ways. There exist grid maps, waypoints, mesh navigation and hierarchical techniques to solve this problem. On randomly generated terrain we make use of automatically generated waypoints to solve pathfinding queries. The waypoints are connected by edges to create a waypoint graph and the graph can be used in real time pathfinding for a single agent in a static environment. This is done by finding the vertices of the blocked triangles from the terrain and place a waypoint on each. We make use of the GPU to create the waypoint graph. The waypoints are connected by utilizing a serialized GPU quad tree to find the relevant blocked geometry to do a line-triangle intersection test. If a line between two waypoints do not intersect any blocked geometry the connection is valid and stored. We found out that it is possible to generate a waypoint graph during the startup of the game with acceptable time results, make use of such a graph for real time pathfinding and that players perceive the paths generated by the algorithm as realistic and responsive. Our conclusion is that our solution is well suited for a deterministic environment with agents of the same size.

[pt] Em terrenos acidentados é crítico para robôs móveis manter uma adequada tração nas rodas, pois um excessivo deslizamento das mesmas pode fazer o robô capotar ou desviar da rota desejada. Também, se uma força excessiva é aplicada sobre uma região do terreno, pode levar o mesmo a ceder deixando as rodas presas. Para se evitar os problemas acima citados e ainda otimizar o consumo de energia em terrenos planos, a presente dissertação desenvolveu um controle de tração para terrenos acidentados com o intuito de aplicá- lo ao Robô Ambiental Híbrido (RAH) da Petrobrás. O RAH é um robô móvel anfíbio que está em fase de desenvolvimento no Laboratório de Robótica do CENPES (Petrobras), que poderá ser comandado por um operador ou se deslocar autonomamente. Esse robô faz parte do projeto Cognitus, braço tecnológico do projeto Piatam (Potenciais Impactos e Riscos Ambientais da Indústria de Óleo e Gás na Amazônia), e será aplicado na monitoração e coleta de dados do meio ambiente de dois gasodutos da Petrobrás na região Amazônica, o gasoduto Urucu (AM)- Porto Velho (RO) e o gasoduto Coari (AM) - Manaus (AM). A técnica de controle de tração de veículos robóticos em terrenos acidentados desenvolvida visa controlar a velocidade ao mesmo tempo em que garante a estabilidade dinâmica, não deslizamento das rodas, evita a saturação dos motores, e em certas condições ainda permite minimizar a potência requerida através do conhecimento dos ângulos de contato entre as rodas e o terreno. Foram feitas duas modelagens independentes, uma considerando a suspensão do robô flexível e a outra considerando o veículo robótico como um corpo rígido, sendo ambas para o caso plano (2D).Foram realizadas simulações em terrenos suaves e acidentados, as quais comprovaram a eficácia das técnicas de controle propostas. / [en] Abstract Silva, Alexandre F. Barral Silva; Meggiolaro, Marco Antonio. Traction Control to Mobile Robotic Systems in Rough Terrain. Rio de Janeiro, 2004. 194 p. MSc. Thesis - Departamento de Engenharia Mecânica, Pontifícia Universidade Católica do Rio de Janeiro. In rough terrain it is critical for mobile robots to maintain adequate wheel traction, because excessive sliding could cause the robot to roll over or deviate from its intended path. Also, if an excessive force is applied onto the terrain, the soil may fail and trap the robot wheels. To avoid these problems, and also minimize the power consumption on even terrain, the present work develops a rough terrain traction control to be applied to the Hybrid Environmental Robot (HER) from Petrobras. The HER is an amphibious mobile robot developed by the Robotics Laboratory from CENPES (Petrobras). It can be commanded by an operator or autonomously. This robot is part of the Cognitus Project, technological branch of the Piatam project (Potential Impacts and Environmental Risks of the Oil and Gas Industry in the Amazon). It will be used for monitoring and environmental data collecting along two gas pipelines in the Amazon region, the Urucu (AM) - Porto Velho (RO) and the Coari (AM) - Manaus (AM). The developed traction control of robotic vehicles in rough terrain aims to control the speed at the same time that it guarantees dynamic stability, no slip of the wheels, prevents motor saturation, and under certain conditions it may also allow for the minimization of the required power. This control needs the knowledge of the current state of the robot, including the contact angles between its wheels and the terrain. Two independent 2D models have been proposed, one including the suspension compliance and one considering the robotic vehicle as a rigid body. Simulations have been performed in even and rough terrains, proving the effectiveness of the proposed control techniques.

[pt] O uso de robôs móveis para monitorar locais inacessíveis vem se tornando cada vez mais comum. Essas operações podem ser autônomas ou tripuladas e quando são feitas em terrenos irregulares é preciso garantir segurança na missão, pois muitas das vezes o resgate se torna inviável. O robô estudado nesta dissertação terá dificuldades para locomoção em certas localidades, como por exemplo: derrapagem em regiões alagadas, vencer atoleiro em regiões pantanosas e de brejos e capotagem nas regiões que apresentam aclives e declives. Diante deste quadro de problemas apresentados, garantir a estabilidade nas regiões de ladeiras é de grande valor nas operações, sejam elas tele-operadas ou autônomas. Visando contribuir para o sucesso da locomoção do robô, esta dissertação apresenta uma técnica de controle de estabilidade de um robô móvel para sensoreamento remoto em terrenos irregulares, incluindo projeto, simulação e construção de um protótipo funcional. Este controle visa garantir que as rodas do veículo não descolem do terreno, através da atuação nas forças de atrito entre as rodas e o solo variando os torques nos seus motores. / [en] The use of mobile robots to monitor non-accessible environments has become increasingly common in the recent years. These tasks can be either autonomous, remote-controlled, or passenger-operated. When performed in rough terrain, it is necessary to guarantee mission safety, since many times it is impossible to send a rescue party for recovery. The hybrid environmental robot presented in this thesis is a mobile robot that will face very challenging conditions, avoiding e.g. slippage in wet terrain, becoming trapped in muddy soil, and tipping over in regions with high slopes. Therefore, it is a challenging task to guarantee robot stability under such circumstances, either in autonomous or operated tasks. This thesis presents a stability control methodology for a mobile robot to perform remote sensing tasks in rough terrain. The model-based technique guarantees wheel-ground contact at all times, acting individually at the wheel motors to control the traction/friction forces. This work also addresses the design, simulation and construction aspects of a functional prototype of a mobile robot to validate the proposed approach.

[pt] O objetivo principal do presente trabalho foi investigar computacionalmente o escoamento e a dispersão de poluentes atmosféricos sobre topografias complexas tridimensionais em escala de laboratório. Foram realizadas simulações numéricas de escoamentos neutros e estavelmente estratificados sobre colinas e também sobre terreno plano. A modelagem matemática, baseada na solução das equações gerais de conservação, inclui o modelo de tensões de Reynolds para a turbulência e um modelo de duas camadas para o tratamento do escoamento na região próxima à parede. O código comercial Fluent (Versão 6.0.12), que emprega o método de volumes finitos, foi utilizado nas simulações computacionais. Os resultados numéricos foram comparados a dados obtidos em experimentos em túnel de vento disponíveis na literatura. Também foram realizadas comparações com resultados obtidos com a utilização do modelo (k menos épsilon) clássico. A comparação entre os resultados obtidos com as diversas modelagens numéricas e os dados experimentais mostrou que a utilização conjunta do modelo de tensões de Reynolds e do tratamento em duas camadas produziu os melhores resultados na predição do escoamento. O desempenho dessa modelagem foi particularmente superior na representação da recirculação no escoamento na região a jusante da colina. Com relação ao cálculo das concentrações, os resultados obtidos foram razoáveis nas regiões mais distantes da fonte quando comparados aos experimentais. Na região mais próxima à fonte emissora, foram calculadas concentrações excessivamente altas ao nível do solo. Estas discrepâncias foram atribuídas ao fato de ter-se utilizado um modelo de difusividade turbulenta isotrópica para os cálculos da dispersão turbulenta do poluente. Ainda assim, os campos de concentrações apresentados mostraram importantes aspectos qualitativos relativos ao problema como, por exemplo, os efeitos da estabilidade atmosférica na dispersão do poluente, que foram adequadamente previstos. / [en] The main objective of the present work was to investigate computationally the flow and the dispersion of atmospheric pollutants over three dimensional complex topographies in laboratory scale. The investigations included the numerical simulation on the neutral and stably stratified flows over hills and flat terrain. The mathematical model was based on the solution of the general conservation equations and included the Reynolds stress model for turbulence and a two layer zonal model for the flow treatment in the near wall region. The commercial code Fluent (Version 6.0.12), which is based on the finite volume method, was employed in the computational simulations. The numerical results were compared to data obtained in wind tunnel experiments, available in the literature. Comparisons were also made with results obtained by employing the standard (k less épsilon) model for turbulence. The comparisons between the experimental data and the numerical results showed that the combined use of the Reynolds stress model and the two layer treatment provided the best results for the flow representation. This modeling approach was particularly superior in representing the flow recirculation on the leeside of the hill. The predicted concentrations results were reasonably good at regions far away from the emission source. In the near source regions, the ground level concentrations were overestimated by the numerical modeling. These discrepancies were attributed to the employment of an isotropic turbulent diffusivity model in the turbulent dispersion calculations. Nevertheless, the calculated concentration fields represented well important qualitative features of PUC Rio.