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Density equalizing distortion of large geographic point sets / P. Bak in Cartography and Geographic Information Science, vol 36 n° 3 (July 2009)
[article]
Titre : Density equalizing distortion of large geographic point sets Type de document : Article/Communication Auteurs : P. Bak, Auteur ; M. Schaefer, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 237 - 250 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique
[Termes IGN] analyse de données
[Termes IGN] cartogramme
[Termes IGN] cartographie statistique
[Termes IGN] densité des points
[Termes IGN] traitement de données localisées
[Termes IGN] visualisation de donnéesRésumé : (Auteur) Visualizing large geo-demographical datasets using pixel-based techniques involves mapping the geospatial dimensions of a data point to screen coordinates and appropriately encoding its statistical value by color. The analysis of such data presents a great challenge. General tasks involve clustering, categorization, and searching for patterns of interest for sociological or economic research. Available visual encodings and screen space limitations lead to over-plotting and hiding of patterns and clusters in densely populated areas, while sparsely populated areas waste space and draw the attention away from the areas of interest. In this paper, two new approaches (RadialScale and AngularScale) are introduced to create density-equalized maps, while preserving recognizable features and neighborhoods in the visualization. These approaches build the core of a multi-scaling technique based on local features of the data described as local minima and maxima of point density. Scaling is conducted several times around these features, which leads to more homogeneous distortions. Results are illustrated using several real-world datasets. Our evaluation shows that the proposed techniques outperform traditional techniques as regard the homogeneity of the resulting data distributions and therefore build a more appropriate basis for analytic purposes. Copyright CaGISociet Numéro de notice : A2009-268 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304009788988288 En ligne : https://doi.org/10.1559/152304009788988288 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29898
in Cartography and Geographic Information Science > vol 36 n° 3 (July 2009) . - pp 237 - 250[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 032-09031 RAB Revue Centre de documentation En réserve L003 Disponible A high resolution orthomosaic in Brazil / N. Parada in Geoinformatics, vol 12 n° 5 (01/07/2009)
[article]
Titre : A high resolution orthomosaic in Brazil Type de document : Article/Communication Auteurs : N. Parada, Auteur ; U.W. Palme, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 22 - 26 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Orthophotographie, orthoimage
[Termes IGN] image à très haute résolution
[Termes IGN] image Ikonos
[Termes IGN] modèle numérique de terrain
[Termes IGN] orthophotoplan numérique
[Termes IGN] réseau géodésique
[Termes IGN] Sao PauloRésumé : (Auteur) A high orthomosaic was generated for the 800 km area of the country of Campinas, Brazil, derived from Ikonos satellite imagery, a Digital Terrain model (DTM) generated from WorldView-1 satellite imagery, and an implemented geodetic network of 19 points. The final orthomosaic was generated both in normal color and in false color infrared in order to broaden the possible applications to environmental issues. This result represents a very interesting solution to cover large areas in short time and with a lower cost than traditional aerophotogrammetric methods, thus with basically the same quality, allowing for a better assertive planning and sustainable development of the territory. Copyright GEOinformatics Numéro de notice : A2009-280 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29910
in Geoinformatics > vol 12 n° 5 (01/07/2009) . - pp 22 - 26[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 262-09051 SL Revue Centre de documentation Revues en salle Disponible Making sense of inter-signal corrections: accounting for GPS satellite calibration parameters in legacy and modernized ionosphere correction algorithms / Avram Tetewsky in Inside GNSS, vol 4 n° 4 (July - August 2009)
[article]
Titre : Making sense of inter-signal corrections: accounting for GPS satellite calibration parameters in legacy and modernized ionosphere correction algorithms Type de document : Article/Communication Auteurs : Avram Tetewsky, Auteur ; Jeff Ross, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : 12 p. ; pp 37 - 48 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] bande L
[Termes IGN] correction ionosphérique
[Termes IGN] effet atmosphérique
[Termes IGN] éphémérides de satellite
[Termes IGN] satellite GPS
[Termes IGN] signal GNSSRésumé : (Auteur) Because satellite designers cannot precisely eliminate small variations in delays among the various signal paths within the spacecraft, GPS signals don’t emerge from the satellite antennas at exactly the same time or from the same location. If not accounted for, these delay offsets would produce navigation fix errors for GPS users. In this article, the authors derive and explain the modernized ionosphere dual- and single-frequency correction algorithms that will resolve these inter-signal variations. They also explain how to modernize any new algorithm, how a single ephemeris models the satellite location when each L-band signal may have separate departure points, and why that one ephemeris might point to a location behind the satellite. Copyright Gibbons Media & Research LLC Numéro de notice : A2009-665 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33566
in Inside GNSS > vol 4 n° 4 (July - August 2009) . - 12 p. ; pp 37 - 48[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 159-09041 SL Revue Centre de documentation Revues en salle Disponible Documents numériques
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Making sense of inter-signal ... - pdf éditeurAdobe Acrobat PDF Tropical cyclone trend analysis using enhanced parallel coordinates and statistical analytics / C.A. Steed in Cartography and Geographic Information Science, vol 36 n° 3 (July 2009)
[article]
Titre : Tropical cyclone trend analysis using enhanced parallel coordinates and statistical analytics Type de document : Article/Communication Auteurs : C.A. Steed, Auteur ; P. Fitzpatrick, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 251 - 265 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse de données
[Termes IGN] corrélation
[Termes IGN] cyclone
[Termes IGN] découverte de connaissances
[Termes IGN] données environnementales
[Termes IGN] données météorologiques
[Termes IGN] données statistiques
[Termes IGN] régressionRésumé : (Auteur) This work presents, via an in-depth case study on how parallel coordinates coupled with statistical analysis can be used for more effective knowledge discovery and confirmation in complex, environmental data sets. Advanced visual interaction techniques such as dynamic axis scaling, conjunctive parallel coordinates, statistical indicators, and aerial perspective shading are combined into an interactive geovisual analytics system. Moreover, the system facilitates statistical processes such as stepwise regression and correlation analysis to assist in the identification and quantification of the most significant predictors for a particular dependent variable. Using a systematic workflow, this approach is demonstrated via a North Atlantic hurricane climate study in close collaboration with a domain expert. By revealing several important physical associations, the case study confirms that the visual analytics approach facilitates a deeper understanding of multidimensional climate data sets when compared to traditional techniques. Copyright CaGISociety Numéro de notice : A2009-269 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304009788988314 En ligne : https://doi.org/10.1559/152304009788988314 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29899
in Cartography and Geographic Information Science > vol 36 n° 3 (July 2009) . - pp 251 - 265[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 032-09031 RAB Revue Centre de documentation En réserve L003 Disponible Where is GIOVE-A exactly? Using microwaves and laser ranging for precise orbit determination / Erik Schönemann in GPS world, vol 20 n° 7 (July 2009)
[article]
Titre : Where is GIOVE-A exactly? Using microwaves and laser ranging for precise orbit determination Type de document : Article/Communication Auteurs : Erik Schönemann, Auteur ; Tim A. Springer, Auteur ; R. Langley, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 42 - 50 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] constellation Galileo
[Termes IGN] GIOVE (satellite)
[Termes IGN] orbitographie
[Termes IGN] télémétrie laser sur satelliteRésumé : (Auteur) We use them for listening to music, for routine surgeries, for making a point in a presentation, and even for hanging pictures straight. Of course, I'm talking about lasers. Invented in 1960, the laser (an acronym for light amplification by the stimulated emission of radiation) has become ubiquitous in modem society. Every CD and DVD player has one. Many printers use them. But lasers are also used in a wide range of industrial and scientific applications including determining the orbits of satellites through satellite laser ranging (SLR). In the SLR technique, pulses of laser light from a ground reference station are directed at satellites equipped with an array of coner-cube retroreflectors, which direct the pulses back towards a collocated receiving, telescope. By accurately measuring the two-way travel times of the pulses and knowing location of the station and other operating parameters, the positions of the satellites can be determined. A network of SLR reference stations around the globe is used to monitor the orbits of satellites over time and their variations have been used by scientists to improve our knowledge of the Earth's gravity field ; to study the long term dynamics of the solid Earth, oceans, and atmosphere; and even to verify predictions of the General Theory of Relativity. The first SLR measurements were obtained from the Beacon Explorer-B satellite which launched in october 1964. Since then, dozens of satellite equipped with corner-cube retroreflectors have been launched including a number of radio-navigation satellites. Every GLONASS satellite is equipped with retroreflectors and two GPS satellite have been equipped - SVN35/PRN05 and SVN36/PNR06. The COMPASS-M1 satellite in medium earth orbit carries retroreflectors, as do both GIOVE-A and -B, the Galileo test satellites. Precise orbit determination of radio-navigation satellites using SLR has the advantage of being unaffected by any onboard satellite electronics and associated signal biases. Radiometric observations of a satellite's microwave signals, on the other hand, are influenced by the satellite's clock, for example, and its effect must be estimated to obtain precise (and accurate) satellite orbits for navigation and positioning. Therefore, a comparison of SLR-and microwave derived orbits can be very useful for studying the performance of the data measurement and orbit-determination processes of both techniques. In this month's column, we take a look at some work being carried out to precisely determine the orbit of the GIOVE-A test satellite using SLR and microwave observations. This preliminary investigation will benefit the procedures to be implemented for the future Galileo constellation. Copyright Questex Media Group Numéro de notice : A2009-282 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29912
in GPS world > vol 20 n° 7 (July 2009) . - pp 42 - 50[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-09071 SL Revue Centre de documentation Revues en salle Disponible Assessment of sliver polygons in geographical vector data / M. Delafontaine in International journal of geographical information science IJGIS, vol 23 n° 6 (june 2009)PermalinkBuilding and mobilizing spatial thinking in civil engineering education / G. Rempel in Geomatica, vol 63 n° 2 (June 2009)PermalinkComparative analysis of SRTM-NED vegetation canopy height to LIDAR-derived vegetation canopy metrics / L. Kenyi in International Journal of Remote Sensing IJRS, vol 30 n°11-12 (June 2009)PermalinkFusion of multi-spectral SPOT-5 images and very high resolution texture information extracted from digital orthophotos for automatic classification of complex Alpine areas / C. Mariz in International Journal of Remote Sensing IJRS, vol 30 n°11-12 (June 2009)PermalinkGénération d'un modèle numérique de terrain Radar : application à la région d'Oran, Algérie / K. Hasni in Bulletin des sciences géographiques, n° 23 (juin 2009)PermalinkHigh resolution DTM process to generate accurate river network for efficient water resource management / G. Prasad Babu in Bulletin des sciences géographiques, n° 23 (juin 2009)PermalinkInfluence of macroscale and microscale surface roughness on multi-beam RADARSAT-1 data: implications for geological mapping in the Curaçá Valley, Brazil / W.R. Paradella in Photo interprétation, European journal of applied remote sensing, vol 45 n° 2 (juin 2009)PermalinkA ''living'' atlas for geospatial storytelling: the cybercartographic atlas of indigenous perspectives ... Atlas of indigenous perspectives and knowledge of the Great Lakes Region in Ontario / Sébastien Caquard in Cartographica, vol 44 n° 2 (June 2009)PermalinkPocket eRelevé : nouvelle approche de collecte de données sur le terrain / Gueyraud Rolland Kipré in Géomatique expert, n° 69 (juin - juillet 2009)PermalinkRelative gravity measurement campaign during the 7th international comparison of absolute gravimeters (2005) / Z. Jiang in Metrologia, vol 46 n° 3 (June 2009)Permalink