Centre de documentation
scientifique

Velocity field and crustal deformation of broader Athens plain (Greece) from a dense geodetic network / Michael Foumelis in Journal of applied geodesy, Vol 13 n° 4 (October 2019)  

Public [article]  inJournal of applied geodesy > Vol 13 n° 4 (October 2019) . - pp 305 – 316 Titre : Velocity field and crustal deformation of broader Athens plain (Greece) from a dense geodetic network Type de document : Article/Communication Auteurs : Michael Foumelis, Auteur Année de publication : 2019 Article en page(s) : pp 305 – 316 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Athènes [Termes IGN] calcul tensoriel [Termes IGN] champ de vitesse [Termes IGN] déformation de la croute terrestre [Termes IGN] extensométrie [Termes IGN] géodynamique [Termes IGN] positionnement par GNSS [Termes IGN] réseau géodésique dense [Termes IGN] tectonique Résumé : (auteur) The broader area of Athens, a region exhibiting relatively low crustal deformation, was stroke in 1999 by a catastrophic earthquake posing serious questions regarding strain accumulation in slow deforming regions located within active geodynamic regimes. In the present study, the establishment of a dense geodetic network, primarily designed to monitor local tectonic movements is reported. A comprehensive GNSS velocity field, over the period 2005–2008, as well as calculated geodetic strain rates is presented. It is shown that a single strain tensor is insufficient to express the heterogeneity of the local geodetic field. Local variability of strain is successfully depicted, indicating the western part of Athens as the area of higher strain accumulation. Maximum dilatation rates occur along a NNE-SSW direction between Parnitha Mt. and Thriasio basin. The observed dilatation can be associated to WNW-ESE trending active fault zones, which appear to abruptly terminate towards East along a major NNE-SSW Miocene tectonic boundary. These findings are consistent to the stress field responsible for the Athens 1999 earthquake, also in agreement with geological and tectonic observations. Finally, the implications of the observed motion field on the understanding of the kinematics and dynamics of the region as well as the role of inherited inactive tectonic structures are discussed. Numéro de notice : A2019-541 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0012 Date de publication en ligne : 04/07/2019 En ligne : https://doi.org/10.1515/jag-2019-0012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94180 [article]

VGI in surveying engineering : Introducing collaborative cloud land surveying / Ioannis Sofos in Journal of Spatial Information Science, JoSIS, n° 15 (September 2017)  

Public [article]  inJournal of Spatial Information Science, JoSIS > n° 15 (September 2017) . - pp 35 - 64 Titre : VGI in surveying engineering : Introducing collaborative cloud land surveying Type de document : Article/Communication Auteurs : Ioannis Sofos, Auteur ; Vassilios Vescoukis, Auteur ; Maria Tsakiri-Strati, Auteur Année de publication : 2017 Article en page(s) : pp 35 - 64 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] Athènes [Termes IGN] données localisées des bénévoles [Termes IGN] entrepôt de données localisées [Termes IGN] géomètre [Termes IGN] informatique en nuage [Termes IGN] partage de données localisées [Termes IGN] topographe Résumé : (Auteur) Volunteered geographic information (VGI) has enabled many innovative applications in various scientific fields. This paper introduces a new framework called “collaborative cloud-based land surveying” (CCLS) that uses VGI principles for data sharing among surveyor engineers to boost the productivity and improve the quality of their applications. A cloud-based spatio-temporal data repository is presented, aiming to facilitate the sharing of VGI among surveyor engineers. A fully-functional distributed software application has been developed and used to apply CCLS in a large-scale land surveying project run by the Greek Ministry of Culture, which involves the mapping of the historic center of Athens. Results from the data analysis of hundreds of measurements indicate a substantial (30% to 60%) error reduction and also a significant productivity raise (22%). The collected measurements are shared in an online database, accessible by professional surveyors who can in turn contribute their own data to further enhance the CCLS system. Numéro de notice : A2017-821 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5311/JOSIS.2017.15.320 En ligne : https://doi.org/10.5311/JOSIS.2017.15.320 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89306 [article]

OpenStreetMap for cadastral purposes: an application using VGI for official processes in urban areas / S. Basiouka in Survey review, vol 47 n° 344 (September 2015)  

Public [article]  inSurvey review > vol 47 n° 344 (September 2015) . - pp 333 - 341 Titre : OpenStreetMap for cadastral purposes: an application using VGI for official processes in urban areas Type de document : Article/Communication Auteurs : S. Basiouka, Auteur ; Chryssy Potsiou, Auteur ; Efthimios Bakogiannis, Auteur Année de publication : 2015 Article en page(s) : pp 333 - 341 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cadastre étranger [Termes IGN] Athènes [Termes IGN] données localisées des bénévoles [Termes IGN] Grèce [Termes IGN] lever cadastral [Termes IGN] OpenStreetMap [Termes IGN] spécification de contenu [Termes IGN] web mapping Résumé : (auteur) The scope of the paper is to test if the online dynamic maps such as the OpenStreetMap (OSM) can be used for official mapping projects such as Cadastre, to investigate the advantages and the concerns of online and open to the public procedures and to identify those differentiations between experts and amateurs that play a critical role in such official projects. The specific research is focused on the use of OSM in urban areas as an alternative method to the official cadastral surveys. This paper presents the possibilities and the perspectives of OSM for spatial and attribute cadastral data collection and storage for the compilation of draft cadastral maps as an alternative methodology within the terms of the volunteered geographic information (VGI). The authors carried out a practical experiment in an extended part of the historic city centre of Athens and updated the online dynamic map of OSM with attribute and spatial cadastral data. Surveying students explored the capacities of the dynamic map in two steps: (a) in a section where the polygons of the buildings already existed on the map, they had to improve it with attribute data, and (b) in another section where no relevant polygons existed, a spatial and attribute data enhancement was required. The research was based on the various approaches that each student adopted and the freedom that the OSM offers to the users. The results show that users can easily distinguish the differences in capacities between the OSM and the commercial software; the inexpensive, easy to use and quick methodology of the OSM in contrast to the accurate, authoritative and assured methodology of the commercial software. Numéro de notice : A2015-917 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1179/1752270615Y.0000000011 En ligne : https://doi.org/10.1179/1752270615Y.0000000011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79708 [article]

Active learning of user’s preferences estimation towards a personalized 3D navigation of geo-referenced scenes / Christos Yiakoumettis in Geoinformatica, vol 18 n° 1 (January 2014)  

Public [article]  inGeoinformatica > vol 18 n° 1 (January 2014) . - pp 27 - 62 Titre : Active learning of user’s preferences estimation towards a personalized 3D navigation of geo-referenced scenes Type de document : Article/Communication Auteurs : Christos Yiakoumettis, Auteur ; Nikolaos Doulamis, Auteur ; Georgios Miaoulis, Auteur ; Djamchid Ghazanfarpour, Auteur Année de publication : 2014 Article en page(s) : pp 27 - 62 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] algorithme génétique [Termes IGN] apprentissage dirigé [Termes IGN] Athènes [Termes IGN] exploration de données [Termes IGN] itinéraire [Termes IGN] métadonnées [Termes IGN] navigation [Termes IGN] ontologie [Termes IGN] optimisation (mathématiques) [Termes IGN] personnalisation [Termes IGN] pondération [Termes IGN] réalité virtuelle [Termes IGN] système d'information géographique [Termes IGN] utilisateur Résumé : (Auteur) The current technological evolutions enter 3D geo-informatics into their digital age, enabling new potential applications in the field of virtual tourism, pleasure, entertainment and cultural heritage. It is argued that 3D information provides the natural way of navigation. However, personalization is a key aspect in a navigation system, since a route that incorporates user preferences is ultimately more suitable than the route with the shortest distance or travel time. Usually, user’s preferences are expressed as a set of weights that regulate the degree of importance of the scene metadata on the route selection process. These weights, however, are defined by the users, setting the complexity to the user’s side, which makes personalization an arduous task. In this paper, we propose an alternative approach in which metadata weights are estimated implicitly and transparently to the users, transferring the complexity to the system side. This is achieved by introducing a relevance feedback on-line learning strategy which automatically adjusts metadata weights by exploiting information fed back to the system about the relevance of user’s preferences judgments given in a form of pair-wise comparisons. Practically implementing a relevance feedback algorithm presents the limitation that several pair-wise comparisons (samples) are required to converge to a set of reliable metadata weights. For this reason, we propose in this paper a weight rectification strategy that improves weight estimation by exploiting metadata interrelations defined through an ontology. In the sequel, a genetic optimization algorithm is incorporated to select the most user preferred routes based on a multi-criteria minimization approach. To increase the degree of personalization in 3D navigation, we have also introduced an efficient algorithm for estimating 3D trajectories around objects of interest by merging best selected 2D projected views that contain faces which are mostly preferred by the users. We have conducted simulations and comparisons with other approaches either in the field of on-line learning or route selection using objective metrics in terms of precision and recall values. The results indicate that our system yields on average a 13.76 % improvement of precision as regards the learning strategy and an improvement of 8.75 % regarding route selection. In addition, we conclude that the ontology driven weight rectification strategy can reduce the number of samples (pair-wise comparisons) required of 76 % to achieve the same precision. Qualitative comparisons have been also performed using a use case route scenario in the city of Athens. Numéro de notice : A2014-027 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10707-013-0176-0 Date de publication en ligne : 12/04/2013 En ligne : https://doi.org/10.1007/s10707-013-0176-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32932 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-2014011	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

Exemplaires(1)

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

Wildfires and remote sensing / Ioannis Z. Gitas in Geoinformatics, vol 10 n° 7 (01/11/2007)

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Urban development in the Athens metropolitan area using remote sensing data with supervised analysis and GIS / Christiane Weber in International Journal of Remote Sensing IJRS, vol 26 n° 4 (February 2005)  

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Mise en évidence de phénomène de subsidence sur la ville d'Athènes (Grèce) lié à la construction du métro par la méthode des points stables en interférométrie radar / S. Van Gorp (2004)

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Geographical city information via internet: development and experience with the city internet map server toolkit / M. Bonazountas in GIM international, vol 15 n° 2 (February 2001)

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SIG, Systèmes d'Information Géographique : les utilisations nouvelles de l'information géographique numérique en urbanisme (actes de la rencontre des 17 et 18 juin 1999) / Direction générale d'urbanisme, habitat et construction (2000)

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Evolutions urbaines d'après des données diachroniques Landsat 3 / Sylvie Rimbert (1985)

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Evolutions urbaines d'après des données diachroniques Landsat 3 (Strasbourg, Athènes, Nanjing) / Sylvie Rimbert (1984)

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tome 27 - 4 /1976 - Télédétection (Bulletin de Méditerranée : revue géographique des pays méditerranéens) / Institut de géographie Université d'Aix-Marseille  

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La charte d'Athènes, entretien avec les étudiants des écoles d'architecture / Le Corbusier (1957)

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L'acropole / W. Hege (1937)

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