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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An automated generalized system for large scale topographic maps

Li, Fang January 1994 (has links)
No description available.
2

Digital Map Based Navigation System For Autonomous Vehicle with DGPS Localization

Ramakrishnan, Balasubramaniam 27 August 2012 (has links)
Autonomous Vehicles (AV) can navigate itself from point `A' to point `B' without the aid of humans. Research on autonomous vehicles were primarily focused on the localization, navigation and path planning schemes. This led to numerous methods in each of the elds of focus. This research focuses on creating a scheme for the autonomous vehicle to navigate using minimal sensors and get maximum data/infor- mation from the map. At rst a digital map contains various structures and each has an associated database. This database contains the details of the environment. At present these data are manipulated for use by humans and for this map to be used with autonomous vehicle require more sensors. This work designs maps for use with autonomous vehicle and navigates using di erential GPS (dGPS) of high accuracy for localization. Then the vehicle gets path and directions from digital map and nav- igates using multiple waypoints that are provided by the path. Finally, the scheme is tested and demonstrated through simulation and test results.
3

Método para o georreferenciamento de mapas urbanos baseado na atribuição de pesos aos pontos de controle / Method for the georreferencing of urban maps based on the attribution of weights to the control points

Santos, Adriana Goulart dos 03 September 2009 (has links)
Para o georreferenciamento das informações extraídas dos mapas digitais são usados modelos matemáticos de transformação geométrica de coordenadas. O desempenho da transformação de coordenadas está diretamente relacionado à exatidão das coordenadas dos pontos de controle identificados no mapa, uma vez que devido ao uso da tecnologia GNSS, não existe mais a dificuldade de se medir com exatidão coordenadas de pontos no terreno. Por esta razão, é possível obter um georreferenciamento admissível se as coordenadas dos pontos de controle forem posicionadas com exatidão sobre o mapa. Entretanto, como na maioria dos municípios do Brasil, os mapas são antigos, ou seja, desatualizados, existe uma dificuldade de se localizar pontos de controle bem determinados dentre os elementos geográficos representados no mapa. Dependendo da qualidade do mapa e pelo modo como foram identificadas no mesmo, estas coordenadas podem apresentar diferentes graus de confiabilidade, em função de suas exatidões. Tal fato, se não for levado em conta, pode prejudicar o desempenho da transformação de coordenadas, e dependendo da escala do mapa, inviabilizar um projeto ou estudo que dependa de uma boa exatidão de coordenadas de pontos oriundas de um produto cartográfico georreferenciado. Para evitar que o desempenho da transformação de coordenadas comprometa a fidelidade do georreferenciamento gerado, é importante que cada coordenada receba um peso apropriado de acordo com a sua exatidão. Neste contexto, o principal objetivo desta pesquisa foi desenvolver um método, validado através de um estudo de caso, que proporcionasse em função da exatidão das coordenadas dos pontos de controle identificadas no mapa digital, um resultado de georreferenciamento admissível a partir do modelo matemático empregado para transformação de coordenadas. Para isso, foi estudado como atribuir o peso ao ponto de controle em função da sua exatidão. A partir disso, o desempenho da transformação de coordenadas usando pesos foi avaliado tanto num mapa de calibração, de boa qualidade, quanto num mapa cuja qualidade posicional era desconhecida. Em ambos os mapas foram realizadas as mais variadas avaliações. Em todas as avaliações efetuadas o desempenho da transformação de coordenadas foi melhor quando foram atribuídos pesos aos pontos de controle em função da sua exatidão. Esta pesquisa levantou uma questão até então desconsiderada, que é a importância de se atribuir pesos às coordenadas dos pontos de controle em função da sua exatidão no mapa digital. O resultado do georreferenciamento se torna admissível quando esta consideração é levada em conta. / The mathematical model for the geometric transformation of coordinates is used to georreference information extrated from digital maps. The performance of coordinate transformation models is directly related to accuracy of control points identified in the map, since by means of the utilization of GNSS technology, it is not difficult to measure the coordinates of a point in the ground with accuracy. For this reason, it is possible to obtain a reliable georreferencing if the coordinates of the control points are accurately positioned on a map. However, as most of brazilian municipal districts maps are old and out-of-date, it is difficult to locate a point accurately out of the geographic elements represented in the map. Depending on both the quality of the digital map and the technique used to locate the points, such coordinates may show distinct levels of reliability as a function of their accuracy. If the different accuracy of the control points is not taking into account, the performance of the coordinate transformation model can be reduced. Depending on map scale, this difference can make impracticable a study that depends on a good accuracy of the coordinates of points obtained from a georreferecend cartographic product. In order to avoid that the performance of the coordinate transformation model reduce the reliability of the georreferencing, it is important that each coordinate receives an appropriate weight according to its accuracy. In this context, the objective of this research was to develop a method, validated through a case study, that could impart reliability to georreferencing, as a function of the accuracy of the coordinates of the control points identified on a map, using a mathematical model to coordinate transformation. The key-point is to attribute a weight to each control point related to its accuracy level. The performance of this procedure was evaluated both for a high quality, standard map, and for a map with unknown quality. Different evaluations were performed and the best results were obtained using the procedure of attributing weights to the control points related its accuracy. As a contribution for the academic and technical areas, this research brought light to a question not considered until now, that is the importance of attributing weights to the coordinates of the control points as a function its accuracy in the digital map. Georreferencing becomes more reliable when this question is taken into account.
4

Método para o georreferenciamento de mapas urbanos baseado na atribuição de pesos aos pontos de controle / Method for the georreferencing of urban maps based on the attribution of weights to the control points

Adriana Goulart dos Santos 03 September 2009 (has links)
Para o georreferenciamento das informações extraídas dos mapas digitais são usados modelos matemáticos de transformação geométrica de coordenadas. O desempenho da transformação de coordenadas está diretamente relacionado à exatidão das coordenadas dos pontos de controle identificados no mapa, uma vez que devido ao uso da tecnologia GNSS, não existe mais a dificuldade de se medir com exatidão coordenadas de pontos no terreno. Por esta razão, é possível obter um georreferenciamento admissível se as coordenadas dos pontos de controle forem posicionadas com exatidão sobre o mapa. Entretanto, como na maioria dos municípios do Brasil, os mapas são antigos, ou seja, desatualizados, existe uma dificuldade de se localizar pontos de controle bem determinados dentre os elementos geográficos representados no mapa. Dependendo da qualidade do mapa e pelo modo como foram identificadas no mesmo, estas coordenadas podem apresentar diferentes graus de confiabilidade, em função de suas exatidões. Tal fato, se não for levado em conta, pode prejudicar o desempenho da transformação de coordenadas, e dependendo da escala do mapa, inviabilizar um projeto ou estudo que dependa de uma boa exatidão de coordenadas de pontos oriundas de um produto cartográfico georreferenciado. Para evitar que o desempenho da transformação de coordenadas comprometa a fidelidade do georreferenciamento gerado, é importante que cada coordenada receba um peso apropriado de acordo com a sua exatidão. Neste contexto, o principal objetivo desta pesquisa foi desenvolver um método, validado através de um estudo de caso, que proporcionasse em função da exatidão das coordenadas dos pontos de controle identificadas no mapa digital, um resultado de georreferenciamento admissível a partir do modelo matemático empregado para transformação de coordenadas. Para isso, foi estudado como atribuir o peso ao ponto de controle em função da sua exatidão. A partir disso, o desempenho da transformação de coordenadas usando pesos foi avaliado tanto num mapa de calibração, de boa qualidade, quanto num mapa cuja qualidade posicional era desconhecida. Em ambos os mapas foram realizadas as mais variadas avaliações. Em todas as avaliações efetuadas o desempenho da transformação de coordenadas foi melhor quando foram atribuídos pesos aos pontos de controle em função da sua exatidão. Esta pesquisa levantou uma questão até então desconsiderada, que é a importância de se atribuir pesos às coordenadas dos pontos de controle em função da sua exatidão no mapa digital. O resultado do georreferenciamento se torna admissível quando esta consideração é levada em conta. / The mathematical model for the geometric transformation of coordinates is used to georreference information extrated from digital maps. The performance of coordinate transformation models is directly related to accuracy of control points identified in the map, since by means of the utilization of GNSS technology, it is not difficult to measure the coordinates of a point in the ground with accuracy. For this reason, it is possible to obtain a reliable georreferencing if the coordinates of the control points are accurately positioned on a map. However, as most of brazilian municipal districts maps are old and out-of-date, it is difficult to locate a point accurately out of the geographic elements represented in the map. Depending on both the quality of the digital map and the technique used to locate the points, such coordinates may show distinct levels of reliability as a function of their accuracy. If the different accuracy of the control points is not taking into account, the performance of the coordinate transformation model can be reduced. Depending on map scale, this difference can make impracticable a study that depends on a good accuracy of the coordinates of points obtained from a georreferecend cartographic product. In order to avoid that the performance of the coordinate transformation model reduce the reliability of the georreferencing, it is important that each coordinate receives an appropriate weight according to its accuracy. In this context, the objective of this research was to develop a method, validated through a case study, that could impart reliability to georreferencing, as a function of the accuracy of the coordinates of the control points identified on a map, using a mathematical model to coordinate transformation. The key-point is to attribute a weight to each control point related to its accuracy level. The performance of this procedure was evaluated both for a high quality, standard map, and for a map with unknown quality. Different evaluations were performed and the best results were obtained using the procedure of attributing weights to the control points related its accuracy. As a contribution for the academic and technical areas, this research brought light to a question not considered until now, that is the importance of attributing weights to the coordinates of the control points as a function its accuracy in the digital map. Georreferencing becomes more reliable when this question is taken into account.
5

Travel Time Estimation Using Sparsely Sampled Probe GPS Data in Urban Road Networks Context

Hadachi, Amnir 31 January 2013 (has links) (PDF)
This dissertation is concerned with the problem of estimating travel time per links in urban context using sparsely sampled GPS data. One of the challenges in this thesis is use the sparsely sampled data. A part of this research work, i developed a digital map with its new geographic information system (GIS), dealing with map-matching problem, where we come out with an enhancement tecnique, and also the shortest path problem.The thesis research work was conduct within the project PUMAS, which is an avantage for our research regarding the collection process of our data from the real world field and also in making our tests. The project PUMAS (Plate-forme Urbaine de Mobilité Avancée et Soutenable / Urban Platform for Sustainable and Advanced Mobility) is a preindustrial project that has the objective to inform about the traffic situation and also to develop an implement a platform for sustainable mobility in order to evaluate it in the region, specifically Rouen, France. The result is a framework for any traffic controller or manager and also estimation researcher to access vast stores of data about the traffic estimation, forecasting and status.
6

Skogen : En studie kring känsla av närhet / The forest : A study of sense of place

Johansson, Frida L. January 2020 (has links)
Denna rapport presenterar en studie som gjorts i samarbete med Södra Skogsägarna. Syftet med studien var att skapa en förståelse för vilka pragmatiska och hedoniska aspekter som påverkar hur skogsägare känner närhet till sin skog och hur dessa aspekter skulle kunna implementeras/realiseras vid utvecklandet av en digital karta över skogen. Genom en kvalitativ studie utifrån en fenomenologisk metodansats kunde en holistisk bild skapas över skogsägare och hur de upplevde känsla av närhet till sin skog. Datainsamlingen bestod av både enkät, intervjuer och fältobservationer som sedan analyserades genom bottom-up och top-down tekniken med hjälp av affinitetsdiagram. Resultatet visar exempelvis att en känsla av närhet är starkt förknippad med att känna ansvar och att kunna påverka kartan utifrån varje enskild skogsägares behov. Studien visar även att en känsla av närhet är nära sammankopplat med egennamn och generation då egennamnen ofta härstammar från tidigare generationer. Skogen används också till rekreation eftersom skogsägare och andra människor mår bra av att vistas i skog och natur. Välmående bidrar då till en ökad känsla av närhet till skogen. Resultatet av studien kommer ligga till grund för kommande utvecklingsprojekt hos Södra Skogsägarna där den digitala kartan i Södras app kommer att ses över. Studien presenterar även UX-mål som bör beaktas vid skapandet av en digital karta för att frambringa känsla av närhet till skogen hos skogsägare. Slutsatsen av studien visar att det är både de pragmatiska och hedoniska aspekterna som tillsammans skapar en helhetsupplevelse av skogen för skogsägare. Denna studie bidrar även med en djupare förståelse och utveckling av begreppet känsla av närhet, för vad och hur skogsägare upplever känsla av närhet till sin skog. Med tanke på dagens snabba teknikutveckling borde framtida forskning fokusera på i vilken utsträckning visualiseringar av skogen kan bidra till ökad känsla av närhet till skogen för skogsägare och om det hos skogsägare finns skillnader mellan genus i hur känsla av närhet till skogen skapas. / This report presents a study done in collaboration with Södra Skogsägarna. The aim of the study was to create an understanding of the pragmatic and hedonic aspects that affect how forest owners feel proximity to their forest and how these aspects could be implemented / realized when developing a digital map of the forest. Through a qualitative study based on a phenomenological method approach, a holistic picture could be created of forest owners and how they experienced sense of place to their forest. The data collection consisted of survey, interviews and field observations, which then were analyzed by bottom-up and top-down technology using affinity diagrams. The result shows, for example, that a sense of place is strongly associated with feeling responsibility and being able to influence the map based on the needs of each individual forest owner. The study also shows that a sense of place is closely associated with proper names and generation, since the proper names often originate from previous generations. The forest is also used for recreation because forest owners and other people feel good about staying in the forest and nature. Well-being then contributes to an increased sense of place to the forest. The results of the study will form the basis for future development projects at Södra Skogsägarna, where the digital map in Södra's app will be reviewed. The study also presents UX goals that should be taken into account when creating a digital map to create a sense of place to the forest among forest owners. The conclusion of the study shows that it is both the pragmatic and hedonic aspects that together create a holistic experience of the forest for forest owners. This study also contributes to a deeper understanding and development of the concept of sense of place, for what and how forest owners experience a sense of place to their forest. Given today's rapid technological development, future research should focus on the extent to which visualizations of the forest can contribute to increased sense of place to the forest for forest owners and whether there are differences between genders in how forest owners create a sense of place to the forest.
7

Travel Time Estimation Using Sparsely Sampled Probe GPS Data in Urban Road Networks Context / Estimation des temps de parcours fondée sur l'utilisation des données éparses de véhicules traceurs dans un contexte urbain

Hadachi, Amnir 31 January 2013 (has links)
Cette thèse porte sur le problème de l'estimation des temps de parcours, de véhicules, par section de route dans un contexte urbain, en utilisant les données GPS à faible densité d’échantillon. L'un des défis de cette thèse est d'utiliser ce genre de données. Dans le cadre de ce travail de recherche, j'ai développé une carte numérique avec son nouveau système d'information géographique (SIG), qui traite la problématique du map-matching, où nous avons apporté des améliorations, ainsi que le problème du plus court chemin.La thèse s'inscrit dans le cadre du projet PUMAS (Plate-forme Urbaine de Mobilité Avancée et Soutenable), ce qui est un avantage pour nos recherches en ce qui concerne le processus de collecte de données réelles sur le terrain ainsi que pour faire nos tests. Le projet PUMAS est un projet préindustriel qui a pour objectif d'informer sur la situation du trafic mais également de développer et de mettre en œuvre une plate-forme de mobilité durable afin de l'évaluer dans la région, notamment à Rouen, France. Le résultat offre un cadre pour tout contrôleur de la situation, gestionnaire ou chercheur pour accéder à de vastes réserves de données sur l'estimation du flux du trafic, sur les prévisions et sur l'état du trafic. / This dissertation is concerned with the problem of estimating travel time per links in urban context using sparsely sampled GPS data. One of the challenges in this thesis is use the sparsely sampled data. A part of this research work, i developed a digital map with its new geographic information system (GIS), dealing with map-matching problem, where we come out with an enhancement tecnique, and also the shortest path problem.The thesis research work was conduct within the project PUMAS, which is an avantage for our research regarding the collection process of our data from the real world field and also in making our tests. The project PUMAS (Plate-forme Urbaine de Mobilité Avancée et Soutenable / Urban Platform for Sustainable and Advanced Mobility) is a preindustrial project that has the objective to inform about the traffic situation and also to develop an implement a platform for sustainable mobility in order to evaluate it in the region, specifically Rouen, France. The result is a framework for any traffic controller or manager and also estimation researcher to access vast stores of data about the traffic estimation, forecasting and status.
8

Kartans roll i skolan och vardagslivet : En beskrivande studie av lärares och elevers uppfattning av kartan som undervisningsmedel på utvalda högstadieskolor / The Map's Function in School and Every-day Life : A describtive study of teachers' and students' perception of the map as an educational aid at chosen junior high schools

Ryrberg, David January 2015 (has links)
Denna studie undersöker hur lärare arbetar med kartor i skolan och hur elever uppfattar användandet av kartor, både i skolan och i vardagslivet. Hur lärare uppfattar förändringen i mötet med kartan genom bytet från Lpo 94 och Lgr 11 kommer också att belysas. För att få svar på dessa frågor har åtta stycken intervjuer av lärare på högstadiet samt fyra fokusgrupper innehållande fyra elever styck genomförts. I intervjuerna uppger lärarna att det idag finns en bristfällig helhetssyn gällande kartan hos eleverna, fokus ligger ofta på ett litet område. Lärarna anser att denna utveckling inom ungdomars kartuppfattning påverkas av dagens teknik, som till exempel GPS där fokus ligger på start- och slutpunkten. Både papperskartor och digitala kartor är nödvändiga för att skapa en strukturerad världsbild där fokus ligger både på det lilla och på det stora menar lärarna. Fem av de intervjuade lärarna anser att de behöver mer kompetens gällande IT för att kunna använda sig mer av digitala kartor. I fokusgrupperna ansåg först de flesta eleverna att de inte mötte kartan överhuvudtaget i vardagslivet, men efter diskussion framgick det att de möter någon form av karta varje dag, som till exempel i dator/Tv-spel, checkar in på ett ställe med Facebook eller söker reda på en adress med hjälp av Google Maps. Bland de 16 elever som var med i fokusgrupperna ansåg 12 stycken att både papperskartan och den digitala kartan behövdes i undervisningen. De ansåg att den digitala kartan, då framförallt Google Earth, var ett roligare verktyg och gjorde lektionstillfällena mer intressanta, men de menade på att en papperskarta ger en bättre helhetsbild av området man skulle undersöka. / This study examines how teachers use the map as an educational aid in school and how students perceive the use of maps, both in school and their every-day life. How do the teachers perceive that the use of maps have changed with the update of the curriculum, from Lpo 94 to Lgr 11 is also going to be elucidated. To answer these questions, eight interviews with junior high school teachers and four focus groups consisting of four students each were done. During the interviews, the teachers stated that students today have a flawed/inadequate/deficient comprehensive view of the map, where focus often lies on a small area. The teachers regard this development of students’ perception of the map as a product of today’s technology, for example GPS where focus lies on finding the starting and ending points. Both paper and digital maps are essential when creating a structured view of the world where focus is both on the small and the big, according to the teachers. Five of the interviewed teachers stated that they need more knowledge about the technology to be able to use digital maps more. In the focus groups, most of the students primarily stated that they did not meet the map at all in their every-day life, but after discussion it was made clear that they meet some kind of map every day, for example in computer/video games, checking in somewhere on Facebook or finding an address with the help of Google Maps. Among the 16 students that participated in the focus groups, 12 stated that both the paper map and the digital map were needed in the education. They think that the digital map, especially Google Earth, is a funnier tool and make the lessons more interesting, but they stated that a paper map provides a better comprehensive picture of the designated area.
9

Compact Digital Track Maps: Enhancing Train Traveller Information at the Crossing of Accuracy and Availability : A comparative analysis of algorithms for generating compact representations of railway tracks / Kompakta digitala spårkartor: Förbättrad information för tågresenärer med nogrannhet och användbarhet i balans : En jämförande analys av algoritmer för att generera kompakta representationer av järnvägsspår

Andersson, Adam January 2023 (has links)
Trains are constrained to the railway tracks they operate on. This can be leveraged for absolute train positioning, where a train’s position can be mapped onto a digital track map (DTM). Extensive research has been dedicated to enhancing the accuracy of DTMs. However, certain practical applications necessitate compact DTMs that can be processed and transferred in real-time, thereby introducing a trade-off between accuracy and memory requirements. This study focuses on data reduction techniques for generating compact DTMs, presenting three distinct methods. Equidistantly sampled Cartesian coordinates are the input to all three methods as they employ different approaches: the linear method simplifies the polygonal chain that connects the coordinates, the spline method utilises smoothing B-splines for interpolation, and the geometric method interpolates the coordinates with a cubic spline and analyse the curvature to identify track segments and describe them geometrically. The performance of these methods is evaluated by their compactness in terms of the number of data fields needed, accuracy in representing track length, and the perpendicular distances between the ground truth track and the generated DTM. The compact DTM generation techniques are applied to three evaluation tracks specifically generated for this study, as well as two existing tracks in the Swedish railway network, each with distinct complexities and characteristics. On the evaluation tracks, the geometrical DTM excels when accuracy is prioritised. As greater perpendicular deviations are tolerated, the smoothed spline DTM method outperforms the other techniques in terms of compactness. The linear DTM method is superior when even greater perpendicular deviations are tolerated. On the existing tracks, the linear DTM method is outperforming the other methods in both accuracy and compactness, presumably because of limitations with the used data set. In conclusion, the choice of technique for generating compact DTMs depends on multiple factors, including the characteristics of the track and the desired level of accuracy. / Tåg är bundna till de järnvägsspår de trafikerar. Detta innebär att tågets digitala position kan förfinas genom att knyta tågets sensorinformation till en position på en digital spårkarta. Tidigare forskning har fokuserat på att förbättra precisionen i digitala spårkartor. Eftersom en del praktiska användningsområden av digitala spårkartor kräver att kartan är kompakt för att kunna bearbetas och överföras i realtid, uppstår en avvägning mellan precision och minneskrav. Denna studie fokuserar således på olika tekniker för datareduktion som kan användas för att generera kompakta spårkartor. Tre metoder tillämpas som alla använder samplade koordinater längs med järnvägsspåret som indata. Den linjära metoden förenklar det polygontåg som förbinder koordinaterna. I spline-metoden används utjämnande splines för att interpolera koordinaterna. Den geometriska metoden interpolerar koordinaterna med en kubisk spline och använder kurvaturen i splinen för att identifiera spårsegment och beskriva dessa geometriskt. De tre metoderna utvärderas och jämförs utifrån en analys avseende kompakthet, avvikelse från järnvägsspårets egentliga längd samt genom att mäta de vinkelräta avstånden mellan det riktiga spåret och spåret i den digitala spårkartan. Tre tågspår har skapats syntetiskt för att utvärdera de tre metoderna. Dessutom har två tågsträckor längs med Kinnekullebanan och Södra stambanan valts ut. Analysen visade att den geometriska spårkartan var mest kompakt på de syntetiska tågspåren när precision prioriterades högst. När kraven på precision minskades var spline-kartan mest kompakt på de syntetiska spåren. Däremot var den linjära metoden mest kompakt när kompakthet prioriterades över precision. Den linjära metoden var dominant med avseende på både precision och kompakthet på Kinnekullebanan och Södra stambanan, troligtvis på grund av begränsningar med den data över järnvägen som använts. Slutsatsen från denna studie är att valet av teknik för att generera kompakta spårkartor beror på flera faktorer, inklusive järnvägsspårets egenskaper och krav på precision.

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