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Digging into the history of VGI data-sets: results from a worldwide study on OpenStreetMap mapping activity / Simon Gröchenig in Journal of location-based services, vol 8 n° 3 ([01/11/2014])
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Titre : Digging into the history of VGI data-sets: results from a worldwide study on OpenStreetMap mapping activity Type de document : Article/Communication Auteurs : Simon Gröchenig, Auteur ; Richard Brunauer, Auteur ; Karl Rehrl, Auteur Année de publication : 2014 Conférence : LBS 2014, 11th International Symposium on Location-Based Services 26/11/2014 28/11/2014 Vienne Autriche Proceedings Taylor&Francis Article en page(s) : pp 198 - 210 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] analyse spatio-temporelle
[Termes IGN] données hétérogènes
[Termes IGN] données localisées des bénévoles
[Termes IGN] jeu de données localisées
[Termes IGN] OpenStreetMap
[Termes IGN] zone ruraleRésumé : (auteur) Volunteered geographic information (VGI) data-sets are characterised by heterogeneity due to influences from technical, social, environmental or economic factors. As a result, mapping progress does neither follow a spatially nor a temporally equal distribution, and thus can be hardly measured or predicted. Positively stated, heterogeneity leads to interesting VGI data-sets revealing regional peculiarities such as diverse community activities. This work proposes an approach for identifying regionally and temporally different developments with respect to mapping progress. Regional mapping progress is measured with a modified version of a previously proposed model for classifying activity stages, which has been used as foundation for a massive spatial and temporal analysis of the worldwide OpenStreetMap contributions between the years 2006 and 2013. It also allows the evaluation of rural and unpopulated areas. Results reveal that regional mapping progress heavily depends on a number of distinct influences such as geographical or legal borders, data imports, unexpected events or diverse community developments. The work highlights regions with distinct results by revealing individual mapping stories. Numéro de notice : A2014-808 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article En ligne : https://doi.org/10.1080/17489725.2014.978403 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85082
in Journal of location-based services > vol 8 n° 3 [01/11/2014] . - pp 198 - 210[article]Assessing reference dataset representativeness through confidence metrics based on information density / Giorgos Mountrakis in ISPRS Journal of photogrammetry and remote sensing, vol 78 (April 2013)
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Titre : Assessing reference dataset representativeness through confidence metrics based on information density Type de document : Article/Communication Auteurs : Giorgos Mountrakis, Auteur ; Bo Xi, Auteur Année de publication : 2013 Article en page(s) : pp 129 - 147 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse de sensibilité
[Termes IGN] carte d'occupation du sol
[Termes IGN] carte de confiance
[Termes IGN] classification dirigée
[Termes IGN] densité d'information
[Termes IGN] données localisées de référence
[Termes IGN] jeu de données localisées
[Termes IGN] representativitéRésumé : (Auteur) Land cover maps obtained from classification of remotely sensed imagery provide valuable information in numerous environmental monitoring and modeling tasks. However, many uncertainties and errors can directly or indirectly affect the quality of derived maps. This work focuses on one key aspect of the supervised classification process of remotely sensed imagery: the quality of the reference dataset used to develop a classifier. More specifically, the representative power of the reference dataset is assessed by contrasting it with the full dataset (e.g. entire image) needing classification. Our method is applicable in several ways: training or testing datasets (extracted from the reference dataset) can be compared with the full dataset. The proposed method moves beyond spatial sampling schemes (e.g. grid, cluster) and operates in the multidimensional feature space (e.g. spectral bands) and uses spatial statistics to compare information density of data to be classified with data used in the reference process. The working hypothesis is that higher information density, not in general but with respect to the entire classified image, expresses higher confidence in obtained results. Presented experiments establish a close link between confidence metrics and classification accuracy for a variety of image classifiers namely maximum likelihood, decision tree, Backpropagation Neural Network and Support Vector Machine. A sensitivity analysis demonstrates that spatially-continuous reference datasets (e.g. a square window) have the potential to provide similar classification confidence as typically-used spatially-random datasets. This is an important finding considering the higher acquisition costs for randomly distributed datasets. Furthermore, the method produces confidence maps that allow spatially-explicit comparison of confidence metrics within a given image for identification of over- and under-represented image portions. The current method is presented for individual image classification but, with sufficient evaluation from the remote sensing community it has the potential to become a standard for reference dataset reporting and thus allowing users to assess representativeness of reference datasets in a consistent manner across different classification tasks. Numéro de notice : A2013-183 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.01.011 En ligne : https://doi.org/10.1016/j.isprsjprs.2013.01.011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32321
in ISPRS Journal of photogrammetry and remote sensing > vol 78 (April 2013) . - pp 129 - 147[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2013041 RAB Revue Centre de documentation En réserve L003 Disponible Semi-automatic quality control of topographic data sets / Petra Helmholz in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 9 (September 2012)
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Titre : Semi-automatic quality control of topographic data sets Type de document : Article/Communication Auteurs : Petra Helmholz, Auteur ; C. Becker, Auteur ; U. Breitkopf, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 959 - 972 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] analyse d'image numérique
[Termes IGN] base de données topographiques
[Termes IGN] contrôle qualité
[Termes IGN] données topographiques
[Termes IGN] image à basse résolution
[Termes IGN] image à haute résolution
[Termes IGN] image aérienne
[Termes IGN] jeu de données localisées
[Termes IGN] réseau sémantiqueRésumé : (Auteur) The usefulness and acceptance of geo-information systems are mainly depends on the quality of the underlying geo-data. This paper describes a novel system for semi-automatic quality control of existing topographic geo-spatial data via automatic image analysis. The goal is to reduce the manual effort for quality control of a GIS database to a minimum. The core of the system is a semantic network in which different image analysis operators can be included. The image analysis operators are created for specific applications, i.e., the quality control of specific object classes which are most relevant. Images which can be used in the system are aerial images, high-resolution satellite imagery, and low-resolution satellite imagery. A prototype of the system has been in use for several years at public mapping organizations. From the experience gained during this time, we give a detailed report on the system performance and an evaluation of the results. Numéro de notice : A2012-443 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.14358/PERS.78.9.959 En ligne : https://doi.org/10.14358/PERS.78.9.959 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31889
in Photogrammetric Engineering & Remote Sensing, PERS > vol 78 n° 9 (September 2012) . - pp 959 - 972[article]
Titre : Change detection in lidar scans of urban environments Type de document : Thèse/HDR Auteurs : Alexandri Gregor Zavodny, Auteur Editeur : South bend [Indiana - Etats-Unis] : University of Notre Dame Année de publication : 2012 Importance : 146 p. Note générale : bibliographie
A dissertation submitted to the Graduate School of the University of Notre Dame in partial fulfillment of the requirements for the degree of doctor of PhilosophyLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] algorithme ICP
[Termes IGN] détection de changement
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] jeu de données localisées
[Termes IGN] Ransac (algorithme)
[Termes IGN] semis de pointsRésumé : (auteur) Light Detection and Ranging (LIDAR) is a popular tool for range sensing applications, with applications including environmental modeling and urban planning. Modern acquisition platforms facilitate data collection rates of over two billion points per hour, enabling the collection of massive datasets with ease. These datasets must typically undergo a large amount of processing before use, making maintenance a difficult issue. Additionally, the presence of transient objects can affect dataset quality, both as unwanted data and by obscuring the underlying surface model. In this dissertation, we present a framework for enabling automatic change detection between large LIDAR datasets of urban environments. For two large scale datasets, we extract the relevant portions using information about the paths of the acquisition vehicles. However, acquisition inaccuracies can result in subset misalignment of up to 10 meters. To correct for this, we utilize a variety of point cloud alignment techniques, including a novel point descriptor, to bring overlapping pieces of data into alignment. Given the properly aligned data, we then use novel hierarchical and point-based techniques to extract regions of change between the two datasets. These regions can then be extracted and presented for further processing or filtering. We present the results of our research executed on datasets totaling over 93 billion sample points. At over 1.5 terabytes in size, this represents by far the largest collection of ground-based LIDAR examined in the open literature. We quantify our results with a variety of objective metrics, investigate modes of failure, and recommend directions for future research. Numéro de notice : 17369 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : PhD thesis : Computer Science and Engineering : Notre Dame Indiana USA : 2012 DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84245 Documents numériques
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Change detection in lidar scansAdobe Acrobat PDF Area aggregation in map generalisation by mixed-integer programming / Jan‐Henrik Haunert in International journal of geographical information science IJGIS, vol 24 n°11-12 (december 2010)
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Titre : Area aggregation in map generalisation by mixed-integer programming Type de document : Article/Communication Auteurs : Jan‐Henrik Haunert, Auteur ; A. Wolff, Auteur Année de publication : 2010 Article en page(s) : pp 1871 - 1897 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] agrégation de données
[Termes IGN] analyse combinatoire (maths)
[Termes IGN] base de données ATKIS
[Termes IGN] base de données topographiques
[Termes IGN] distance
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] graphe
[Termes IGN] jeu de données localisées
[Termes IGN] méthode heuristique
[Termes IGN] optimisation (mathématiques)
[Termes IGN] programmation par contraintes
[Termes IGN] rédaction cartographique
[Termes IGN] sémiologie graphique
[Vedettes matières IGN] GénéralisationRésumé : (Auteur) Topographic databases normally contain areas of different land cover classes, commonly defining a planar partition, that is, gaps and overlaps are not allowed. When reducing the scale of such a database, some areas become too small for representation and need to be aggregated. This unintentionally but unavoidably results in changes of classes. In this article we present an optimisation method for the aggregation problem. This method aims to minimise changes of classes and to create compact shapes, subject to hard constraints ensuring aggregates of sufficient size for the target scale. To quantify class changes we apply a semantic distance measure. We give a graph theoretical problem formulation and prove that the problem is NP-hard, meaning that we cannot hope to find an efficient algorithm. Instead, we present a solution by mixed-integer programming that can be used to optimally solve small instances with existing optimisation software. In order to process large datasets, we introduce specialised heuristics that allow certain variables to be eliminated in advance and a problem instance to be decomposed into independent sub-instances. We tested our method for a dataset of the official German topographic database ATKIS with input scale 1:50,000 and output scale 1:250,000. For small instances, we compare results of this approach with optimal solutions that were obtained without heuristics. We compare results for large instances with those of an existing iterative algorithm and an alternative optimisation approach by simulated annealing. These tests allow us to conclude that, with the defined heuristics, our optimisation method yields high-quality results for large datasets in modest time. Numéro de notice : A2010-554 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810903401008 En ligne : https://doi.org/10.1080/13658810903401008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30746
in International journal of geographical information science IJGIS > vol 24 n°11-12 (december 2010) . - pp 1871 - 1897[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-2010071 RAB Revue Centre de documentation En réserve L003 Disponible 079-2010072 RAB Revue Centre de documentation En réserve L003 Disponible IRSJ : incremental refining spatial joins for interactive queries in GIS / W. Bae in Geoinformatica, vol 14 n° 4 (October 2010)PermalinkFusion d'images optique et radar à haute résolution pour la mise à jour de bases de données cartographiques / Vincent Poulain (2010)PermalinkLocation-based algorithms for finding sets of corresponding objects over several geo-spatial data sets / E. Safra in International journal of geographical information science IJGIS, vol 24 n°1-2 (january 2010)PermalinkFinding anomalies in high-density Lidar point clouds / J. Harrison in Geomatica, vol 63 n° 4 (December 2009)PermalinkModelling the erectheion: extracting information from very large datasets / J. Beraldin in GIM international, vol 23 n° 11 (November 2009)PermalinkA flexible multi-source spatial-data fusion system for environmental status assessment at continental scale / P. Carrara in International journal of geographical information science IJGIS, vol 22 n° 6-7 (june 2008)PermalinkTechniques for computing fitness of use (FoU) for time series datasets with applications in the geospatial domain / L. Fu in Geoinformatica, vol 12 n° 1 (March - May 2008)PermalinkGestion des mises à jour concurrentes dans des jeux de données géographiques répartis / Christelle Pierkot (18/06/2007)PermalinkDesigning visual analytics methods for massive collections of movement data / Natalia Adrienko in Cartographica, vol 42 n° 2 (June 2007)PermalinkLocal statistical spatial analysis [LoSSA]: Inventory and prospect / B. Boots in International journal of geographical information science IJGIS, vol 21 n° 3-4 (march - april 2007)PermalinkAn integrated approach for modelling and global registration of point clouds / T. Rabbani in ISPRS Journal of photogrammetry and remote sensing, vol 61 n° 6 (February 2007)PermalinkPermalinkGoogle Earth: pour voler comme superman / T. Rousselin in SIG la lettre, n° 79 (septembre 2006)PermalinkA web interface to explore and restructure geographical datasets / Sandrine Balley (2006)PermalinkAutomatic change detection and updating of topographic databases by using satellite imagery : a level set approach / M.S. Allili in Geomatica, vol 59 n° 3 (September 2005)PermalinkOptimization approaches for generalization and data abstraction / Monika Sester in International journal of geographical information science IJGIS, vol 19 n° 8 - 9 (september 2005)PermalinkThe use of remote sensing techniques and empirical tectonic models for inference of geological structures: bridging from regional to local scales / P.C. Fernandes Da Silva in Remote sensing of environment, vol 96 n° 1 (15/05/2005)PermalinkAide à l’acquisition de données géographiques sur mesure : Extraction et restructuration via le schéma de données / Sandrine Balley (2005)PermalinkImproving geographical datasets usability by interactive schema transformations / Sandrine Balley (2005)PermalinkModelling heterogeneous and distributed spatial datasets to support updates management / Christelle Pierkot (2005)Permalink