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Titre : Eleven International Workshop on Database and expert systems applications : 4-8 September, 2000 Greenwich, London, UK Type de document : Actes de congrès Auteurs : A M Tjoa, Éditeur scientifique ; R.R. Wagner, Éditeur scientifique ; A. Al-Zobaidie, Éditeur scientifique Editeur : New-York : IEEE Computer society Année de publication : 2000 Conférence : DEXA 2000, 11th International Conference Database and Expert Systems Applications 04/09/2000 08/09/2000 Londrs Royaume-Uni Importance : 1164 p. Format : 21 x 27 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] base de données orientée objet
[Termes IGN] entrepôt de données
[Termes IGN] exploration de données
[Termes IGN] exploration de données géographiques
[Termes IGN] flux de travaux
[Termes IGN] indexation
[Termes IGN] synchronisation
[Termes IGN] XMLNuméro de notice : 17097 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Actes En ligne : https://archive.org/details/springer_10.1007-3-540-44469-6 Format de la ressource électronique : URL contenu Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79529 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 17097-01 CG2000 Livre Centre de documentation Congrès Disponible Visualization of relationships between spatial patterns in time by cartographic animation / Connie Blok in Cartography and Geographic Information Science, vol 26 n° 2 (April 1999)
[article]
Titre : Visualization of relationships between spatial patterns in time by cartographic animation Type de document : Article/Communication Auteurs : Connie Blok, Auteur ; B. Kobben, Auteur ; A.A. Kuterema, Auteur Année de publication : 1999 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique
[Termes IGN] cartographie animée
[Termes IGN] données localisées numériques
[Termes IGN] espace-temps
[Termes IGN] synchronisation
[Termes IGN] transport collectif
[Termes IGN] visualisation dynamiqueRésumé : (Auteur) This paper deals with dynamic visualization methods. The focus is on synchronization, one of the aspects that can dynamically control visualization. Synchronization refers to the possibility of running several animations simultaneously and manipulating their starting points in display time to discover relationships. The literature provides examples where animations are juxtaposed to discover (usually) causal relations. Can synchronization be relevant for other relationships ? How complex is its application in practice ? And are there alternatives for the perceptually difficult juxtaposing of animations ? We investigated design options for the visual exploration and analysis of three relationships between spatial patterns in time : convergence, similarity, and stability. For each relationship we used two data sets to produce experimental designs, in which we tried to incorporate knowledge on vision and cognition. It seems useful to distinguish between synchronization in world and in display time. If it is not necessary to view the data sets separately and to manipulate them independently in display time, one animation is sufficient. In other cases, two animations and, sometimes, alternative options for juxtaposing seem useful. However, empirical testing is still required to determine whether the proposed tools are effective. The experimental designs discussed in this paper are published on the Web. Numéro de notice : A1999-182 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304099782330716 En ligne : https://doi.org/10.1559/152304099782330716 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26379
in Cartography and Geographic Information Science > vol 26 n° 2 (April 1999)[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 032-99021 RAB Revue Centre de documentation En réserve L003 Disponible Dynamic GPS height determination in the decimeter level for bathymetric applications / Robert Lemmens (1993)
Titre : Dynamic GPS height determination in the decimeter level for bathymetric applications Type de document : Monographie Auteurs : Robert Lemmens, Auteur Editeur : Delft [Pays-Bas] : Delft University of Technology Année de publication : 1993 Collection : LGR-SERIES num. 4 Importance : 110 p. Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] bathymétrie
[Termes IGN] GPS en mode différentiel
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement dynamique
[Termes IGN] précision décimétrique
[Termes IGN] propagation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] synchronisation
[Termes IGN] temps réel
[Termes IGN] trajet multipleIndex. décimale : 30.70 Navigation et positionnement Résumé : (Auteur) This research treats the feasibility of using GPS for accurate height determination of the echo sounder transducer in bathymetric applications. Positioning should be possible in the decimeter level after proper resolution of the carrier phase integer cycle ambiguity. On-the-fly ambiguity resolution techniques are used to accomplish this in a dynamic environment. To test dynamic GPS relative positioning performance, a short-baseline experiment was carried out with a wave simulator which produced an accurate reference trajectory. Using L1 carrier phase observations and C/A-code observations with a 7-satellite configuration, heights in the centimeter level were achieved after an initialization period of a few minutes. Several parts of the experiment show the importance of redundant satellites and the vulnerability of the ambiguity resolution to periodic errors and cycle slips. Dynamics in height direction of 10 cm/s do not seem to affect the ambiguity resolution process, but increase the noise level of the resulting positions. In practice baselines of a few tens of kilometers also need knowledge of atmospheric delays. Assuming these effects are well modeled, which seems feasible at the moment, and multipath is reduced, height determination is possible with an accuracy of about one decimeter for baselines of a few tens of kilometers and 1-2 decimeter for longer baselines. A high confidence level of the positions can be obtained by thorough quality control, as can be achieved by statistical testing on cycle slips and outliers. The reliability of the system will be increased by several redundant observations like simultaneously measuring 7 or more satellites, multiple reference stations, using an external timebase, etc. Finally to explore full GPS accuracy in the bathymetric survey, aspects of integrating GPS, the echo sounder and additional measurements are considered. Although relative GPS heights as obtained in this research are very well applicable in several survey applications, the decimeter accuracy of absolute heights seems still difficult to achieve when these heights are needed with respect to an absolute levelling datum, because the local relation between the levelling datum and the WGS84 ellipsoid is often not well known. Other aspects like sensor offset and time synchronization also appear to be important when integrating GPS in a bathymetric surveying system. Numéro de notice : 18207 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55349 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 18207-01 30.70 Livre Centre de documentation Géodésie Disponible