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Adaptive time-variant adjustment for the positioning errors of a mobile mapping platform in GNSS-hostile areas / Jiawei Han in Survey review, vol 49 n° 352 (March 2017)  

Public [article]  inSurvey review > vol 49 n° 352 (March 2017) . - pp 9 - 14 Titre : Adaptive time-variant adjustment for the positioning errors of a mobile mapping platform in GNSS-hostile areas Type de document : Article/Communication Auteurs : Jiawei Han, Auteur ; C.P. Lo, Auteur Année de publication : 2017 Article en page(s) : pp 9 - 14 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] couplage GNSS-INS [Termes IGN] erreur de positionnement [Termes IGN] GNSS assisté pour la navigation [Termes IGN] occultation du signal [Termes IGN] positionnement par GNSS [Termes IGN] système de numérisation mobile [Termes IGN] zone urbaine dense Résumé : (Auteur) A mobile mapping system (MMS) utilizes global navigation satellite system (GNSS) and inertial navigation system (INS) techniques and thus makes possible a direct geo-referencing solution everywhere along its surveyed path. It is capable of acquiring a vast amount of spatial information in an efficient manner and is adopted in a wide variety of applications. However, when the GNSS signal is obstructed, its positioning solution can only rely on the INS observables, which acquire significant and cumulative errors over time. In this study, an adaptive time-variant adjustment model is proposed to compensate for the MMS positioning error in a GNSS-hostile area using ground calibration points. Based on the results from a case study, it illustrates that the positioning error of a mobile mapping platform in an urban area for a long time could reach a level of several metres because of GNSS signal obstructions. However, this error can be properly modelled and significantly reduced to a centimetre-level when the proposed approach is applied. Consequently, both the efficiency and reliability of the MMS applications in a GNSS hostile environment can be further guaranteed. Numéro de notice : A2017-057 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2015.1104091 En ligne : https://doi.org/10.1080/00396265.2015.1104091 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84265 [article]

Mining trajectory data and geotagged data in social media for road map inference: Mining social media for road map inference / Jun Li in Transactions in GIS, vol 19 n° 1 (February 2015)  

Public [article]  inTransactions in GIS > vol 19 n° 1 (February 2015) . - pp 1 - 18 Titre : Mining trajectory data and geotagged data in social media for road map inference: Mining social media for road map inference Type de document : Article/Communication Auteurs : Jun Li, Auteur ; Qiming Qin, Auteur ; Jiawei Han, Auteur ; Lu-An Tang, Auteur ; Kin Hou Lei, Auteur Année de publication : 2015 Article en page(s) : pp 1 - 18 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] base de données routières [Termes IGN] contenu généré par les utilisateurs [Termes IGN] données localisées des bénévoles [Termes IGN] exploration de données géographiques [Termes IGN] géobalise [Termes IGN] inférence [Termes IGN] mise à jour de base de données [Termes IGN] traitement du langage naturel Résumé : (auteur) As mapping is costly and labor-intensive work, government mapping agencies are less and less willing to absorb these costs. In order to reduce the updating cycle and cost, researchers have started to use user generated content (UGC) for updating road maps; however, the existing methods either rely heavily on manual labor or cannot extract enough information for road maps. In view of the above problems, this article proposes a UGC-based automatic road map inference method. In this method, data mining techniques and natural language processing tools are applied to trajectory data and geotagged data in social media to extract not only spatial information – the location of the road network – but also attribute information – road class and road name – in an effort to create a complete road map. A case study using floating car data, collected by the National Commercial Vehicle Monitoring Platform of China, and geotagged text data from Flickr and Google Maps/Earth, validates the effectiveness of this method in inferring road maps. Numéro de notice : A2015--118 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1111/tgis.12072 Date de publication en ligne : 15/01/2014 En ligne : http://doi.wiley.com/10.1111/tgis.12072 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102453 [article]

Efficient polygon amalgamation methods for spatial OLAP and spatial data mining / X. Zhou (20/07/1999)  

Public contenu dans Advances in spatial data bases, SSD '99, 6th International Symposium, Hong Kong, China, July 20-23, 1999 / Ralf Hartmut Güting (1999)   Titre : Efficient polygon amalgamation methods for spatial OLAP and spatial data mining Type de document : Article/Communication Auteurs : X. Zhou, Auteur ; D. Truffet, Auteur ; Jiawei Han, Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 20/07/1999 Conférence : SSD 1999, 6th International Symposium Advances in spatial data bases 20/07/1999 23/07/1999 Hong Kong Chine Proceedings Springer Importance : pp 167 - 187 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] exploration de données géographiques [Termes IGN] indexation spatiale [Termes IGN] OLAP [Termes IGN] polygone [Termes IGN] regroupement de données [Termes IGN] requête spatiale [Termes IGN] SOLAP Résumé : (Auteur) The polygon amalgamation operation computes the boundary of the union of a set of polygons. This is an important operation for spatial on-line analytical processing and spatial data mining, where polygons representing different spatial objects often need to be amalgamated by varying criteria when the user wants to aggregate or reclassify these objects. The processing cost of this operation can be very high for a large number of polygons. Based on the observation that not all polygons to be amalgamated contribute to the boundary, we investigate in this paper efficient polygon amalgamation methods by excluding those internal polygons without retrieving them from the database. Two novel algorithms, adjacency-based and occupancy-based, are proposed. While both algorithms can reduce the amalgamation cost significantly, the occupancy-based algorithm is particularly attractive because : 1) it retrieves a smaller amount of data than the adjacency-based algorithm ; 2) it is based on a simple extension to a commonly used spatial indexing mechanism ; and 3) it can handle fuzzy amalgamation. Numéro de notice : C1999-058 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Communication DOI : 10.1007/3-540-48482-5_12 En ligne : https://doi.org/10.1007/3-540-48482-5_12 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65824