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Quality assessment and accessibility mapping in an image-based geocrowdsourcing testbed / Matthew T. Rice in Cartographica, vol 53 n° 1 (Spring 2018)  

Public [article]  inCartographica > vol 53 n° 1 (Spring 2018) . - pp 1 - 14 Titre : Quality assessment and accessibility mapping in an image-based geocrowdsourcing testbed Type de document : Article/Communication Auteurs : Matthew T. Rice, Auteur ; Dan Jacobson, Auteur ; Dieter Pfoser, Auteur ; Kevin M. Curtin, Auteur ; Han Qin, Auteur ; et al., Auteur Année de publication : 2018 Article en page(s) : pp 1 - 14 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] accessibilité [Termes IGN] données localisées des bénévoles [Termes IGN] handicap [Termes IGN] production participative [Termes IGN] qualité des données Résumé : (Auteur) Geocrowdsourcing is a significant new focus area in mapping for people with disabilities. It utilizes public data contributions that are difficult to capture with traditional mapping workflows. Along with the benefits of geocrowdsourcing are critical drawbacks, including reliability and accuracy. A geocrowdsourcing testbed has been designed to explore the dynamics of geocrowdsourcing and quality assessment and produce temporally relevant navigation obstacle data. These reports are then used for route planning, obstacle avoidance, and spatial awareness. Recently, the geocrowdsourcing testbed has been modified to focus on the contribution of images and short descriptions, rather than the more lengthy previous reporting process. The quality assessment workflow of the geocrowdsourcing testbed is contrasted with a modified quality assessment workflow, implemented in the simpler and quicker image-based reporting paradigm. General quality assessment of data position and temporal characteristics is still possible, while general data attributes and detail are now supplied by a moderator from the contributed image. The derivation of obstacle location from multiple intersected image direction vectors does not produce reliable results, but an approach using buffered convex hulls works dependably. This simpler, quicker geocrowdsourcing workflow produces geocrowdsourced obstacle data and quality assessment estimates for location, time, and attribute accuracy. Numéro de notice : A2018-206 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3138/cart.53.1.2017-0013 Date de publication en ligne : 21/03/2018 En ligne : https://doi.org/10.3138/cart.53.1.2017-0013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89922 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
031-2018011	SL	Revue	Centre de documentation	Revues en salle	Disponible

Hub Labels on the database for large-scale graphs with the COLD framework / Alexandros Efentakis in Geoinformatica, vol 21 n° 4 (October - December 2017)  

Public [article]  inGeoinformatica > vol 21 n° 4 (October - December 2017) . - pp 703 - 732 Titre : Hub Labels on the database for large-scale graphs with the COLD framework Type de document : Article/Communication Auteurs : Alexandros Efentakis, Auteur ; Christodoulos Efstathiades, Auteur ; Dieter Pfoser, Auteur Année de publication : 2017 Article en page(s) : pp 703 - 732 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] base de données localisées [Termes IGN] chemin le plus court, algorithme du [Termes IGN] compression de données [Termes IGN] graphe [Termes IGN] plus proche voisin, algorithme du [Termes IGN] SQL Résumé : (Auteur) Shortest-path computation on graphs is one of the most well-studied problems in algorithmic theory. An aspect that has only recently attracted attention is the use of databases in combination with graph algorithms, so-called distance oracles, to compute shortest-path queries on large graphs. To this purpose, we propose a novel, efficient, pure-SQL framework for answering exact distance queries on large-scale graphs, implemented entirely on an open-source database engine. Our COLD framework (COmpressed Labels on the Database) can answer multiple distance queries (vertex-to-vertex, one-to-many, k-Nearest Neighbors, Reverse k-Nearest Neighbors, Reverse k-Farthest Neighbors and Top-k Range) not handled by previous methods, rendering it a complete database solution for a variety of practical large-scale graph applications. Our experimentation shows that COLD outperforms existing approaches (including popular graph databases) in terms of query time and efficiency, while requiring significantly less storage space than these methods. Numéro de notice : A2017-601 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-016-0287-5 En ligne : https://doi.org/10.1007/s10707-016-0287-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86909 [article]

Crowdsourcing urban form and function / Andrew Crooks in International journal of geographical information science IJGIS, vol 29 n° 5 (May 2015)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 29 n° 5 (May 2015) . - pp 720 - 741 Titre : Crowdsourcing urban form and function Type de document : Article/Communication Auteurs : Andrew Crooks, Auteur ; Dieter Pfoser, Auteur ; Andrew Jenkins, Auteur Année de publication : 2015 Article en page(s) : pp 720 - 741 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse de données [Termes IGN] données localisées des bénévoles [Termes IGN] données ouvertes [Termes IGN] milieu urbain [Termes IGN] modélisation spatiale [Termes IGN] morphologie urbaine [Termes IGN] OpenStreetMap [Termes IGN] surveillance de l'urbanisation [Termes IGN] système d'information géographique Résumé : (Auteur) Urban form and function have been studied extensively in urban planning and geographical information science. However, gaining a greater understanding of how they merge to define the urban morphology remains a substantial scientific challenge. Toward this goal, this paper addresses the opportunities presented by the emergence of crowdsourced data to gain novel insights into form and function in urban spaces. We are focusing in particular on information harvested from social media and other open-source and volunteered datasets (e.g. trajectory and OpenStreetMap data). These data provide a first-hand account of form and function from the people who define urban space through their activities. This novel bottom-up approach to study these concepts complements traditional urban studies to provide a new lens for studying urban activity. By synthesizing recent advancements in the analysis of open-source data, we provide a new typology for characterizing the role of crowdsourcing in the study of urban morphology. We illustrate this new perspective by showing how social media, trajectory, and traffic data can be analyzed to capture the evolving nature of a city’s form and function. While these crowd contributions may be explicit or implicit in nature, they are giving rise to an emerging research agenda for monitoring, analyzing, and modeling form and function for urban design and analysis. Numéro de notice : A2015-592 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2014.977905 En ligne : https://doi.org/10.1080/13658816.2014.977905 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77881 [article]

vol 10 n° 1 - March - May 2006 - Selected papers from ACM GIS'04 [actes 12-13 november 2004, Arlington, USA] (Bulletin de Geoinformatica) / Dieter Pfoser  

Public [n° ou bulletin]  est un bulletin de Geoinformatica (1997 -)   Titre : vol 10 n° 1 - March - May 2006 - Selected papers from ACM GIS'04 [actes 12-13 november 2004, Arlington, USA] Type de document : Périodique Auteurs : Dieter Pfoser, Éditeur scientifique ; I. Cruz, Éditeur scientifique Année de publication : 2006 Conférence : ACM GIS 2004, 12th ACM symposium on geographic information systems 12/11/2004 13/11/2004 Arlington Etats-Unis Selected papers Importance : 120 p. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique Numéro de notice : 057-0601 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Numéro de périodique En ligne : http://link.springer.com/journal/10707/10/1/page/1 Format de la ressource électronique : URL sommaire Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=8772 [n° ou bulletin]

Contient

• Utilizing Voronoi cells of location data streams for accurate computation of aggregate functions in sensor networks / M. Sharifzadeh in Geoinformatica, vol 10 n° 1 (March - May 2006)  
• Detecting roads in stabilized video with the spatio-temporal structure tensor / R. Plessl in Geoinformatica, vol 10 n° 1 (March - May 2006)  
• An ontology-based approach to personalized situation-aware mobile service supply / N. Weissenberg in Geoinformatica, vol 10 n° 1 (March - May 2006)  
• Building and querying a P2P virtual world / Hanan Samet in Geoinformatica, vol 10 n° 1 (March - May 2006)  

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-06011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Indeterminacy and spatiotemporal data: Basic definitions and case study / Dieter Pfoser in Geoinformatica, vol 9 n° 3 (September - November 2005)  

Public [article]  inGeoinformatica > vol 9 n° 3 (September - November 2005) . - pp 211 - 236 Titre : Indeterminacy and spatiotemporal data: Basic definitions and case study Type de document : Article/Communication Auteurs : Dieter Pfoser, Auteur ; Nectaria Tryfona, Auteur ; C. Jensen, Auteur Année de publication : 2005 Article en page(s) : pp 211 - 236 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Information géographique [Termes IGN] données spatiotemporelles [Termes IGN] extension temporelle [Termes IGN] incertitude de position [Termes IGN] incertitude géométrique [Termes IGN] logique floue [Termes IGN] modélisation spatio-temporelle [Termes IGN] objet géographique [Termes IGN] objet mobile Résumé : (Auteur) For some spatiotemporal applications, it can be assumed that the modeled world is precise and bounded, and that also our record of it is precise. While these simplifying assumptions are sufficient in applications like a land information system, they are unnecessarily crude for many other applications that manage data with spatial and/or temporal extents, such as navigational applications. This work explores fuzziness and uncertainty, subsumed under the term indeterminacy, in the spatiotemporal context. To better illustrate the basic spatiotemporal concepts of change or evolution, it is shown how the fundamental modeling concepts of spatial objects, attributes, and relationships and time points and periods are influenced by indeterminacy and how they can be combined. In particular, the focus is on the change of spatial objects and their geometries across time. Four change scenarios are outlined, which concern discrete versus continuous change and asynchronous versus synchronous measurement, and it is shown how to model indeterminacy for each. A case study illustrates the applicability of the paper's general proposal by describing the uncertainty related to the management of the movements of point objects, such as the management of vehicle positions in a fleet management system. Numéro de notice : A2005-325 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-005-1282-4 En ligne : https://doi.org/10.1007/s10707-005-1282-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27461 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-05031	RAB	Revue	Centre de documentation	En réserve L003	Disponible