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scientifique

Visualization, statistical analysis, and mining of historical vessel data / Sabarish Senthilnathan Muthu (2015)  

Public Titre : Visualization, statistical analysis, and mining of historical vessel data Type de document : Mémoire Auteurs : Sabarish Senthilnathan Muthu, Auteur Editeur : Fredericton [Canada] : University of New Brunswick Année de publication : 2015 Collection : Technical report num. 296 Importance : 150 p. Format : 21 x 30 cm Note générale : bibliographie M.Sc.E. thesis, Department of Geodesy and Geomatics Engineering Langues : Anglais (eng) Descripteur : [Termes IGN] données spatiotemporelles [Termes IGN] Egée, mer [Termes IGN] interface web [Termes IGN] navire [Termes IGN] site Natura 2000 [Termes IGN] trajectoire (véhicule non spatial) [Vedettes matières IGN] Géovisualisation Résumé : (auteur) An important area of research in marine information systems is the management and analysis of the large and increasing amount maritime spatio-temporal datasets. There are a lack of systems that may provide visualization and clustering techniques for large spatiotemporal datasets (Oliveira, 2012). This thesis describes the design and implementation of a prototype web-based system for visualizing, computing statistics, and detecting outliers of moving vessels over a massive set of historic AIS data from the Aegean Sea in the Mediterranean. This historic AIS data was acquired from the Marine Traffic project (Marine Traffic, 2014) which collects the raw location points of the vessels. The web-based system provides the following functionalities: (i) user interface to upload the location points of vessels into a database, (ii) detailed and simplified trajectory construction of the uploaded location points of vessels, (iii) distance, speed, direction, and turn angle computation of the constructed trajectories, (iv) identify vessels that intersect the European Union’s Natura 2000 protected areas, (v) identify spatio-temporal outliers in the location points of vessels using DBSCAN algorithm, and (vi) heat map visualization to show the traffic load and highlight sea zones of high risk. The architecture of the web-based system employed is based on open standards, and allows for interoperable data access. The system was implemented using PHP as the server-side scripting language, and Google Maps API as the client-side scripting language. Furthermore, improved system responsiveness, and server performance was achieved by asynchronous interaction between client and server by utilizing AJAX to send and receive requests. In addition, data transfer between client and server was achieved using the platform-independent and light weight JSON format. Numéro de notice : 14918 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Mémoire masters divers En ligne : http://www2.unb.ca/gge/Pubs/TR296.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76912

The development of integrated terrestrial and marine pathways in the Argo-Saronic region, Greece / J. M. L. Newhard in Cartography and Geographic Information Science, vol 41 n° 4 (September 2014)  

Public [article]  inCartography and Geographic Information Science > vol 41 n° 4 (September 2014) . - pp 379 - 390 Titre : The development of integrated terrestrial and marine pathways in the Argo-Saronic region, Greece Type de document : Article/Communication Auteurs : J. M. L. Newhard, Auteur ; N. S. Levine, Auteur ; A. D. Phebus, Auteur Année de publication : 2014 Article en page(s) : pp 379 - 390 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] âge du bronze [Termes IGN] chemin le moins coûteux, algorithme du [Termes IGN] Egée, mer [Termes IGN] Grèce [Termes IGN] voie de communication Résumé : (auteur) Least cost path applications can be a powerful tool for understanding connectivity across a landscape. A limitation to this method is its difficulty in integrating terrestrial, marine, and cultural factors – all of which would have been at play in the prehistoric Aegean. This study looks at a method of modeling pathways that integrates major factors (land, sea, and culture) that would be in play while considering medium- to long-distance travel in the Aegean. This test case explores the possible relationships between proposed routes for communication and identified coastal sites with parameters modeled in geographic information system that affect travel in cultural, marine, and terrestrial contexts. The methods presented have significance beyond the Late Bronze Age Aegean. The development of a methodology that incorporates marine, cultural, and terrestrial environments provides a mechanism by which specific hypotheses regarding complex communication routes may be addressed in regions of the world where there is an intensive interplay between terrestrial and marine geographies. Numéro de notice : A2014-432 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2014.925786 En ligne : https://doi.org/10.1080/15230406.2014.925786 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=73969 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-2014041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Estimation of the zero-height geopotential level WoLVD in a local vertical datum from inversion of co-located GPS, leveling and geoid heights: a case study in the Hellenic islands / Christopher Kotsakis in Journal of geodesy, vol 86 n° 6 (June 2012)  

Public [article]  inJournal of geodesy > vol 86 n° 6 (June 2012) . - pp 423 - 439 Titre : Estimation of the zero-height geopotential level WoLVD in a local vertical datum from inversion of co-located GPS, leveling and geoid heights: a case study in the Hellenic islands Type de document : Article/Communication Auteurs : Christopher Kotsakis, Auteur ; K. Katsambalos, Auteur ; Dimitrios Ampatzidis, Auteur Année de publication : 2012 Article en page(s) : pp 423 - 439 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] champ de pesanteur terrestre [Termes IGN] Egée, mer [Termes IGN] Grèce [Termes IGN] modèle de géopotentiel local [Termes IGN] niveau moyen des mers [Termes IGN] réseau altimétrique local [Termes IGN] zéro hydrographique Résumé : (Auteur) The estimation of the zero-height geopotential level of a local vertical datum (LVD) is a key task towards the connection of isolated physical height frames and their unification into a common vertical reference system. Such an estimate resolves, in principle, the ‘ambiguity’ of a traditional crust-fixed LVD by linking it with a particular equipotential surface of Earth’s gravity field under the presence of an external geopotential model. The aim of this paper is to study the estimation scheme that can be followed for solving the aforementioned problem based on the joint inversion of co-located GPS and leveling heights in conjunction with a fixed Earth gravity field model. Several case studies with real data are also presented that provide, for the first time, precise estimates of the LVD offsets for a number of Hellenic islands across the Aegean and Ionian Sea. Numéro de notice : A2012-244 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0530-7 Date de publication en ligne : 03/12/2011 En ligne : https://doi.org/10.1007/s00190-011-0530-7 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31690 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-2012061	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Analysis of long-term GPS observations in Greece (1993-2009) and geodynamic implications for the Eastern Mediterranean / Michael D. Müller (2011)  

Public Titre : Analysis of long-term GPS observations in Greece (1993-2009) and geodynamic implications for the Eastern Mediterranean Type de document : Rapport Auteurs : Michael D. Müller, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2011 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 82 Importance : 186 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-28-4 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Athènes [Termes IGN] champ de vitesse [Termes IGN] collocation par moindres carrés [Termes IGN] Egée, mer [Termes IGN] Grèce [Termes IGN] méthode des éléments finis [Termes IGN] Péloponnèse [Termes IGN] séisme [Termes IGN] vitesse Index. décimale : 30.82 Applications géophysiques de géodésie spatiale Résumé : (Auteur) The Global Positioning System (GPS) is used to determine rates of crustal motion in the Hellenic plate boundary zone since the late eighties. The zone comprises Greece and its adjacent regions. It is characterized by the interaction of the Eurasian, Anatolian and Nubian plates moving relative to each other. Tectonic processes associated with this motion cause the highest seismic activity of Europe. Nine earthquakes with magnitude six or higher occurred within this region in the period 2006 to 2011. International efforts are being made to achieve a better understanding of the origin and characteristics of ongoing seismotectonic processes. The ETH Zurich has taken active part in these efforts. Results achieved so far provide valuable boundary conditions for geodynamic modeling. In close collaboration with other institutes an extensive GPS network has been established and periodically remeasured. The network consists of campaign-type and continuous GPS sites. The corresponding data record has been significantly extended in the course of the thesis. A 16 year record of GPS data (19932009) is available now for Greece. In its first part the thesis deals with the evaluation of the data record. The strategy of GPS analysis was enhanced compared to proceeding projects by applying recent GPS processing models and improving postprocessing procedures. The concept of including data of numerous IGS and EUREF sites located in Europe, North Africa and the Middle East was continued. This allowed for a precise alignment of the GPS network to a global reference frame (ITRF2005), the reduction of processing induced systematic signals and the determination of a pole of rotation for the Eurasian plate. An improved kinematic field was derived which was analyzed in terms of slowly deforming regions by using a block model. The modeling provides several insights. For instance, northwestern Greece rotates clockwise (cw) and the region south of the North Aegean trough (NAT) rotates counterclockwise (ccw) relative to Eurasia. Both areas form blocks with small internal deformation. Moreover, they describe the western termination of the North Aegean trough. A large part of ongoing deformation is located in confined regions. The GPS derived deformation field provides information about ongoing tectonic processes. These include N-S extension between Northern Greece and the Gulf of Corinth and dextral shear strain in the North Aegean sea as well as along the Kefalonia fault zone in the Ionian sea. New results concerning ongoing deformation processes were achieved in the Southeast Aegean sea and in Northern Greece. Pronounced N-S extension (100 nstrain/yr) was determined across the Mygdonian graben. NNW-SSE extension amounting to 150 nstrain/yr was found between the islands of Kalymnos and Tilos in the SE Aegean sea. The NAT and the Kefalonia fault zone are among the most pronounced transform faults in the Hellenic plate boundary zone. Rates of closely located GPS sites were used for the estimation of the slip rates and locking depths of the structures. Four profiles across the NAT show a decrease of slip rates from the Ganos fault (23 mm/yr) towards the southwestern edge of the Sporades basin (<5 mm/yr). The geodetic results provide further evidence that the NAT forms the westward continuation of the North Anatolian fault zone commencing at the Saros basin. The decrease of slip rates west of the Chalkidiki peninsula is related to a different orientation of the NAT and to NNE-SSW extension in the Sporades basin. Finite element models were used to relate GPS rates to basic geodynamic models. The first model I focused at the analysis of the subduction rate near the central Hellenic trench. The results point to a largely uncoupled interface between the Nubian and Aegean plates. The second model quantifies the slip rates along the three major NE-SW to ENE-WSW trending transform faults in the North Aegean sea. Rates amounting to 21 mm/yr were derived for the NAT, 10 mm/yr for the Skyros- Edremit fault and 4 mm/yr for the Psara-Lesvos fault. Moreover, the model reveals additional deformation zones such as NNE-SSW extension in the Sporades basin. The derived GPS rates and the conducted analyses improve the current understanding of seismotectonic processes in Greece. The investigations also highlight remaining problems and bring forward new ideas which will ultimately be valuable for further analysis and assessment of natural hazard in Greece. Note de contenu : 1 Introduction 1.1 State of research 1.2 Goals 2 Geologic setting 2.1 Evolution of the central and eastern Mediterranean 2.2 Tectonic framework of Greece 3 GPS data evaluation 3.1 Description of relevant GPS networks 3.1.1 Campaign-type GPS network in Greece and southern Bulgaria 3.1.2 Continuous GPS networks in Greece 3.1.3 IGS and EUREF sites 3.2 Strategy of GPS data processing 3.3 Definition of the geodetic datum 3.4 Velocity estimation of CGPS sites 3.4.1 Introduction 3.4.2 Discontinuities in position time series 3.4.3 Removing outliers 3.4.4 Exclusion periods 3.4.5 Estimation of velocities and offsets 3.4.6 Reduction of apparent scale changes of the processed GPS network 3.4.7 Scaling of formal errors of velocities 3.5 Velocity estimation of campaign-type GPS sites 3.6 Factors affecting the velocity estimates 3.6.1 Tracking performance of GPS sites 3.6.2 Used orbits and earth orientation parameters 3.6.3 Campaign-type data of the years 1993 and 1994 3.7 Concluding remarks 4 Kinematic field in Greece (19932009) 4.1 Introduction 4.2 Euler vector and estimation of a pole of rotation for Eurasia (ITRF2005) 4.3 Kinematic block model for Greece 4.4 Kinematic field and modeling in the North Aegean domain 4.4.1 Kinematic field 4.4.2 Slip rates and locking depths along the North Aegean trough 4.5 Kinematics along the Hellenic trench system 4.5.1 Ionian islands, Western Greece and NW Peloponnesos 4.5.2 Southern Peloponnesos and South Aegean sea 4.6 Vertical motion in Greece 4.7 Concluding remarks 5 Strain rates derived by using the method of collocation 5.1 Least-squares collocation 5.2 Velocity and strain rate fields calculation implemented in the program 'strain' 5.3 Strain rates and differential rotations in Greece 5.4 Concluding remarks 6 Seismic signals in GPS time series 6.1 Introduction 6.2 Estimation of earthquake displacements 6.3 Analytical surface dislocation model 6.4 Earthquakes in the Aegean domain 6.4.1 1999 Ms 5.9 Athens earthquake 6.4.2 2001 Mw 6.4 Skyros earthquake 6.4.3 2008 Mw 6.4 Rhodes earthquake 6.5 Earthquakes in the Ionian sea 6.5.1 1997 Mw 6.6 Strofades earthquake 6.5.2 2003 Mw 6.2 Lefkada earthquake 6.5.3 2006 Zakynthos earthquake series 6.5.4 2008 Mw 6.4 NW Peloponnesos earthquake 6.5.5 Comparison of seismicity and interseismic strain rates 6.6 Concluding remarks 7 Finite element models 7.1 Finite element method 7.1.1 Basic theory 7.1.2 Displacement-based finite element analysis 7.2 Physical properties of a model lithosphere 7.2.1 Introductory notes 7.2.2 Elasticity 7.2.3 Brittle failure 7.2.4 Ductile deformation 7.2.5 Temperature in the continental lithosphere 7.3 Interaction between the overriding and the subducting plate at the central Hellenic trench 7.3.1 Geodetic constraints 7.3.2 Developed finite element model 7.4 3D finite element model of the North Aegean sea 7.4.1 Introduction 7.4.2 Model set up 7.4.3 Results 7.5 Concluding remarks 8 Conclusions Numéro de notice : 14311 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport de recherche En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-82.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62654

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
14311-01	30.82	Livre	Centre de documentation	Géodésie	Disponible

Sea surface topography and marine geoid by airborne laser altimetry and shipborne ultrasound altimetry / Philippe Limpach (2010)  

Public Titre : Sea surface topography and marine geoid by airborne laser altimetry and shipborne ultrasound altimetry Type de document : Thèse/HDR Auteurs : Philippe Limpach, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2010 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 80 Importance : 208 p. Format : 20 x 30 cm ISBN/ISSN/EAN : 978-3-908440-24-6 Note générale : Bibliographie Doctoral thesis Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] anomalie de pesanteur [Termes IGN] bathymétrie acoustique [Termes IGN] Crète (île) [Termes IGN] données Jason [Termes IGN] Egée, mer [Termes IGN] géoïde altimétrique [Termes IGN] géoïde local [Termes IGN] geoïde marin [Termes IGN] géoréférencement direct [Termes IGN] GPS en mode cinématique [Termes IGN] GPS en mode différentiel [Termes IGN] océanographie dynamique [Termes IGN] relief de la surface de la mer [Termes IGN] sondage acoustique [Termes IGN] surface de la mer [Termes IGN] télémétrie laser aéroporté [Termes IGN] validation des données Index. décimale : 30.83 Applications océanographiques de géodésie spatiale Résumé : (Auteur) The aim of this project was to contribute to the improvement of sea level monitoring and to provide local-scale information on the short-wavelength structure of the marine gravity field, by developing enhanced methods for offshore sea surface height observations. The methods include airborne laser altimetry, shipborne ultrasound altimetry and GPS-equipped buoys. In a first step, instrumental aspects of sea surface height observations by airborne and shipborne altimetry were analyzed. Precise position and attitude of the range sensor are crucial for an accurate sea surface height computation. For this purpose, the survey aircraft and boat were equipped with a multi-antenna GPS array and inertial systems. Sea surface heights were computed from the range data by direct georeferencing. Important aspects are the influences of errors in the differential kinematic GPS positioning and in the attitude determination, as well as the calibration of boresight misalignments. In a second step, the obtained sea surface heights were reduced to mean sea surface by applying corrections for geophysical effects, including waves, tides, atmospheric pressure and wind forcing. In the framework of this work, several regional campaigns for sea surface height surveys based on airborne and shipborne altimetry were carried out in the Eastern Mediterranean Sea. Dedicated surveys, including deployments of GPS buoys, were performed along Jason-1 radar altimetry ground tracks. Airborne laser altimetry data was acquired along densely spaced flight tracks covering an area of 200 by 200km around the western part of the island of Crete, Greece, in the vicinity of the Hellenic Trench. The objective was the determination of a detailed regional geoid and sea surface topography model in the framework of the GAVDOS project, funded by the European Union. Furthermore, several shipborne campaigns for sea surface height observations were carried out in the North Aegean Sea, in the vicinity of the North Aegean Trough. Based on the airborne and shipborne altimetry data, a high-resolution sea surface topography of the survey areas was computed, with an accuracy of better than 10 cm. Geoid undulations were derived from the sea surface heights by subtracting the mean dynamic ocean topography induced by oceanic currents. Around western Crete, the geoid obtained from airborne laser altimetry is characterized by very large gradients, with an average height difference of 20m along a distance of only 200km and maximum local gradients of 22 cm/km. These gradients are a clear indication for significant gravity effects caused by the bathymetry and the geodynamic system of the Hellenic Trench. In the survey area in the North Aegean Sea, the geoid obtained from shipborne altimetry shows a distinct depression of 1.5 m, indicating a connection with the bathymetry and the geodynamic features of the North Aegean Trough. The high resolution and accuracy of the sea surface and geoid heights obtained were verified by comparisons with mean sea surface models from multi-mission satellite radar altimetry, as well as with global and regional geoid models. The reduction of the geoid heights for modeled mass effects of topography, bathymetry, marine sedimentary deposits and crust-mantle boundary revealed pronounced gravity anomalies related to the geodynamic processes in the survey areas. Note de contenu : 1 Introduction 1.1 Motivation and Goals 1.2 Geophysical Characteristics of the Eastern Mediterranean 1.3 Former Work by the GGL in Related Fields of Research 1.4 Research Tasks and Project Outline 2 Geoid, Sea Surface and Dynamic Ocean Topography 2.1 Introduction 2.2 Geoid 2.3 Mean Sea Surface 2.4 Sea Level Anomaly 2.5 Dynamic Ocean Topography 2.6 Permanent Tide 3 Geophysical Effects on Sea Surface Heights 3.1 Introduction 3.2 Ocean Waves 3.3 Tides 3.4 Atmospheric Pressure and Wind Forcing 4 Airborne Laser Altimetry 4.1 Introduction 4.2 Instumental Setup 4.3 Laser Ranging 4.4 Laser Backscatter from Sea Surface 5 Shipborne Ultrasound Altimetry 5.1 Introduction 5.2 Instrumental Setup 5.3 Ultrasound Ranging 5.4 Sensor Synchronization 6 Direct Georeferencing 6.1 Introduction 6.2 Basic Principle 6.3 Kinematic GPS Positioning 6.4 Multi-Antenna GPS Attitude Determination 6.5 Boresight Misalignment Calibration in Airborne Altimetry 7 Sea Surface Heights by Airborne Laser Altimetry around Western Crete 7.1 GAVDOS Airborne Laser Altimetry Campaign 7.2 Instantaneous Sea Surface Height Profiles 7.3 Sea Surface Height Corrections 7.4 Repeatability Analysis 7.5 Time-Independent Sea Surface Topography 8 Sea Surface Heights by Shipborne Ultrasound Altimetry in the North Aegean Sea 8.1 Shipborne Ultrasound Altimetry Campaigns 8.2 Instantaneous Sea Surface Height Profiles 8.3 Sea Surface Height Corrections 8.4 Repeatability Analysis 8.5 Time-Independent Sea Surface Topography 9 Validation of Satellite Radar Altimetry Data 9.1 Introduction 9.2 Validation of Jason-1 Data with Airborne Laser Altimetry 9.3 Validation of Mean Sea Surface from Radar Altimetry 10 Geoscientific Exploitation of Airborne Altimetry Data around Western Crete 10.1 Marine Geoid, Gravity Anomalies and Deflections of the Vertical from Sea Surface Heights 10.2 Local Altimetric Geoid vs. Existing Models 10.3 Mean Dynamic Topography Estimation 10.4 Modeled Mass Effects on Geoid Heights and Gravity 10.5 Mass Reduction of Local Altimetric Geoid 11 Geoscientific Exploitation of Shipborne Altimetry Data in the North Aegean Sea 11.1 Marine Geoid, Gravity Anomalies and Deflections of the Vertical from Sea Surface Heights 11.2 Local Altimetric Geoid vs. Existing Models 11.3 Mean Dynamic Topography Estimation 11.4 Modeled Mass Effects on Geoid Heights and Gravity 11.5 Mass Reduction of Local Altimetric Geoid 12 Summary and Conclusions Numéro de notice : 10369 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-005876550 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-80.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62408

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
10369-01	30.83	Livre	Centre de documentation	Géodésie	Disponible

Present-day crustal dynamics in the Adriatic-Aegean plate boundary zone inferred from continuous GPS-measurements / Yannick Peter (2001)  

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Les marées / M.A. Courtier (1937)

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