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Multi-scale rendering with geometry collapse and a symbol knowledge Base / J. Choi in Cartographic journal (the), vol 46 n° 2 (May 2009)  

Public [article]  inCartographic journal (the) > vol 46 n° 2 (May 2009) . - pp 155 - 163 Titre : Multi-scale rendering with geometry collapse and a symbol knowledge Base Type de document : Article/Communication Auteurs : J. Choi, Auteur ; C. Hwang, Auteur Année de publication : 2009 Article en page(s) : pp 155 - 163 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique [Termes IGN] base de connaissances [Termes IGN] base de données professionnelles [Termes IGN] généralisation cartographique automatisée [Termes IGN] objet géographique linéaire [Termes IGN] représentation multiple [Termes IGN] symbole graphique Résumé : (Auteur) This paper discusses a novel methodology for multi-scale rendering of geographic features depending upon changes in visual scale. The methodology consists of geometry collapse and a symbol knowledge base. Two collapse algorithms are implemented: polygon to point and polygon to line. In particular, we develop a partial collapse algorithm for linear features. A river is represented by lines and polygons depending on the width. To render features with scale changes, a symbol knowledge base is designed to specify scale ranges and symbols for each feature. Finally, a multi-scale rendering tool is developed and applied to the map of Camp Lejune, NC. The symbols in the knowledge base can be accumulated and adapted for various mapping applications. Copyright British Cartographic Society Numéro de notice : A2009-266 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1179/000870409X459914 En ligne : https://doi.org/10.1179/000870409X459914 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29896 [article]

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030-09021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Satellite Altimetry for geodesy, geophysics and oceanography / C. Hwang (2004)  

Public Titre : Satellite Altimetry for geodesy, geophysics and oceanography : Proceedings of the International Workshop on satellite altimetry, a joint workshop of IAG section 3 Special study group SSG3.186 and IAG section 2, September 8-13, 2002, Wuhan, China Type de document : Actes de congrès Auteurs : C. Hwang, Éditeur scientifique ; C.K. Shum, Éditeur scientifique ; J. Li, Éditeur scientifique Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2004 Collection : International Association of Geodesy Symposia, ISSN 0939-9585 num. 126 Conférence : IAG 2002, International Workshop on satellite altimetry, a joint workshop of IAG section 3 Special study group SSG3.186 and IAG section 2, Satellite Altimetry for geodesy, geophysics and oceanography 13/08/2002 Wuhan Chine Importance : 280 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 3-540-420211-0 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] altimétrie satellitaire par radar [Termes IGN] circulation océanique [Termes IGN] géodésie spatiale [Termes IGN] géophysique [Termes IGN] océanographie spatiale Résumé : (Editeur) This volume covers a broad range of altimetry applications, including marine gravity and geoïd, sea level change, ocean tide modeling, ocean circulations, marine plate tectonics, mesoscale eddies and bathymetry predictions. Virtually all disciplines of earth sciences are touched upon through the technique of satellite altimetry. Readers will find useful data processing techniques and movel applications of satellite altimetry, which otherwise are scattered in journals and special books. Note de contenu : KEYNOTE SPEECHES Geodetic Applications of Satellite Altimetry Present-day Sea Level Rise : from Satellite and in Situ Observations to Physical Causes Advances in Large-scale Ocean Dynamics from a Decade of Satellite Altimetric Measurement of Ocean Surface Topography GEODETIC APPLICATIONS Calibration Results of GFO Determination of 30'x 30'Marine Gravity Anomalies from Multisatellite Altimetry Recovering Deflections of Vertical from Tangent Plane of Gridded Geoidal Heights from Altimetry Marine Gravity Anomaly from Satellite Altimetry: a Comparison of Methods over Shallow Waters Enhanced Free6air Gravity Anomalies by Satellite Radar Altimetry Topex Altimetric Mean Sea Level and Gravimetric Geoid in the North of Algeria A Modified Method for Recovering Bathymetry from Altimeter Data Absolute Calibration of the ERS-2 Altimeter using UK Tide Gauges An Intercomparison of Parametric Models of Sea State Bias for the TOPEX,Poseidon and Jason- I Altimeters Determination of Global Mean Sea Surface Using Multi-satellite Altimetric Data Pseudo-Harmonic Representation of Gravity Field over South China Sea GEOPHYSICAL AND OCEANOGRAPHIC APPLICATIONS Investigation of Hydrological and Atmospheric Loading by Space Geodetic Techniques Joint Application of Altimeter Data and EGM96 to Submarine Tectonic and Geodynamic Study in West Pacific Bathymetry and Crustal Thickness Variations from Gravity Inversion and Flexural Isostasy. Comparisons of Three Inversion Approaches for Recovering Gravity Anomalies From Altimeter Data Accuracy Assessment of Gravity Field Models by Independent Satellite Crossover Altimetry Low Frequency Change of Sea Level in the North Atlantic Ocean as Observed with Satellite Altimetry Application of Satellite Remote Sensing on the Tuna Fishery of Eastern - Tropical Pacific The Kinematics of Mesoscale Eddies from TOPEX/POSEIDON Altimetry over the Subtropical Counter Current OCEANOGRAPHIC APPLICATIONS Oceanography with GPS Geostrophic Uncertainty and Anomalous Current Structure in Association.with Mesoscale Eddies Delineated by Altimeter Observations East of Taiwan Current Variability over the Scotian Slope in the 1990s Determination of Sea Level Height Variation by Dynamics Crossover Adjustment Extreme Southern Ocean Tide Modeling The M4 Shallow Water Tidal Constituent From Altimetry and Tide Gauges Harmonic Tidal Analysis Along T/P Tracks in China Seas and Vicinity Analysis of Temporal Sea Level Variation in the Barents and the White Seas from Altimetry, Tide Gauges and Hydrodynamic Simulation The Envisat Radar Altimeter System Absolute Comparison of Satellite Altimetry and Tide Gauge Registrations in Venezuela Sea Level Changes Detected by Using Satellite Altimeter Data and Comparing with Tide Gauge Records in China Sea Numéro de notice : 18912 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Actes DOI : 10.1007/978-3-642-18861-9 En ligne : https://doi.org/10.1007/978-3-642-18861-9 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=34884

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18912-01	CG2002	Livre	Centre de documentation	Congrès	Disponible

Orthogonal functions over the oceans and applications to the determination of orbit error, geoid and sea surface topography from satellite altimetry / C. Hwang (1991)

Public Titre : Orthogonal functions over the oceans and applications to the determination of orbit error, geoid and sea surface topography from satellite altimetry Type de document : Monographie Auteurs : C. Hwang, Auteur Editeur : Colombus (Ohio) : Ohio State University Année de publication : 1991 Collection : Department of Geodetic Science and Surveying Reports num. 414 Importance : 229 p. Format : 21 x 27 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie [Termes IGN] altimétrie satellitaire par radar [Termes IGN] fonction orthogonale [Termes IGN] géoïde altimétrique [Termes IGN] océan [Termes IGN] orbite [Termes IGN] surface de la mer Index. décimale : 30.04 Mathématiques appliquées à la géodésie Résumé : (Auteur) The goal of this study is to look for a set of orthogonal functions over the oceans and then to apply the functions to the expansions of oceanic signals. Ultimately these functions are incorporated in the parameter estimation problem using a model that simultaneously reduces satellite radial orbit errors, improves the geoid and estimates the sea surface topography. To construct a possible set of orthogonal functions (over the oceans), three methods have been studied. In one method, an attempt was made to solve the spherical Helmholtz equation over the oceans with either the Dirichlet boundary condition or the Newmann Boundary condition or the mixed boundary condition. This method leads to successful developments of the spherical cap harmonics and generalized Fourier-Bessel series for some regularized oceanic domains. The other study employs the Shwarz-Christoffel conformal mapping, as well as an auxiliary mapping, to transform the irregular domain (the oceans) onto the interior of a unit disk where a set of orthogonal functions are easy to find. The set of orthogonal functions over the oceans are then found through the relationship between the two domains implied by the mappings. The third method involves the GramSchmidt process for which a new technique for computing the integrals of the products of two associated Legendre functions is developed and a FFT method is used to compute the inner products of spherical harmonics over the oceans. Also, for the entire unit sphere, the generalized 2-D Fourier series and the generalized Fourier-Tschebycheff series are proposed as alternatives for the spherical harmonics. The expansions of the Levitus SST into the orthonormal functions constructed by the Gram-Schmidt process show that 98.5% of the energy of that signal is contained within degree 10 of the orthonormal functions. Such expansions also render regular spectral behavior of oceanic signal as compared to that from spherical harmonic expansions. A method of detecting band limited oceanic signal is also developed using these orthonormal functions. The applications of these functions to the simultaneous model yield lower correlation between expansion coefficients and show that the cut-off frequency (the highest degree determinable) of the SST from the Geosat data is in the vicinity of degree 15 of the functions. Some other improved simultaneous models have also been tested in an attempt to better separate the geoid and the SST signal. This study concludes that the orthonormal functions are suitable for representing oceanic signal with excellent spectral behavior and c be applied to future altimetric mission such as TOPEX/POSEIDON. Numéro de notice : 12114 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54542

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