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Machine learning and geodesy: A survey / Jemil Butt in Journal of applied geodesy, vol 15 n° 2 (April 2021)  

Public [article]  inJournal of applied geodesy > vol 15 n° 2 (April 2021) . - pp 117 - 133 Titre : Machine learning and geodesy: A survey Type de document : Article/Communication Auteurs : Jemil Butt, Auteur ; Andreas Wieser, Auteur ; Zan Gojcic, Auteur ; Caifa Zhou, Auteur Année de publication : 2021 Article en page(s) : pp 117 - 133 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Intelligence artificielle [Termes IGN] analyse de données [Termes IGN] apprentissage automatique [Termes IGN] données géodésiques [Termes IGN] espace de Hilbert [Termes IGN] méthode fondée sur le noyau Résumé : (Auteur) The goal of classical geodetic data analysis is often to estimate distributional parameters like expected values and variances based on measurements that are subject to uncertainty due to unpredictable environmental effects and instrument specific noise. Its traditional roots and focus on analytical solutions at times require strong prior assumptions regarding problem specification and underlying probability distributions that preclude successful application in practical cases for which the goal is not regression in presence of Gaussian noise. Machine learning methods are more flexible with respect to assumed regularity of the input and the form of the desired outputs and allow for nonparametric stochastic models at the cost of substituting easily analyzable closed form solutions by numerical schemes. This article aims at examining common grounds of geodetic data analysis and machine learning and showcases applications of algorithms for supervised and unsupervised learning to tasks concerned with optimal estimation, signal separation, danger assessment and design of measurement strategies that occur frequently and naturally in geodesy. Numéro de notice : A2021-321 Affiliation des auteurs : non IGN Thématique : INFORMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2020-0043 Date de publication en ligne : 20/02/2021 En ligne : https://doi.org/10.1515/jag-2020-0043 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97478 [article]

The influence of sea-level changes on geodetic datums along the east coast of China / Yang Liu in Marine geodesy, vol 44 n° 1 (January 2021)  

Public [article]  inMarine geodesy > vol 44 n° 1 (January 2021) . - pp 26 - 41 Titre : The influence of sea-level changes on geodetic datums along the east coast of China Type de document : Article/Communication Auteurs : Yang Liu, Auteur ; Chuanyin Zhang, Auteur ; Baogui Ke, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 26 - 41 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse harmonique [Termes IGN] champ de pesanteur terrestre [Termes IGN] changement du niveau de la mer [Termes IGN] Chine [Termes IGN] déformation de la croute terrestre [Termes IGN] données géodésiques [Termes IGN] données spatiotemporelles [Termes IGN] fonction de Green [Termes IGN] littoral [Termes IGN] surveillance du littoral [Termes IGN] système de référence local Résumé : (Auteur) Non-tidal variation on sea level generates immediate changes in gravity field and deformation of the Earth’s crust, thus influencing the stability of geodetic datums. To achieve higher accuracy of geodetic datums in coastal and island areas, sea-level changes should be adequately considered when conducting the maintenance of datums. Based on the data of sea-level anomalies from 2014 to 2017 and the theory of load-deformation of elastic spherical earth, this paper demonstrates that impacts of non-tidal ocean load can be quantitatively calculated on geodetic datums along the east coast of China, by using removerestore technique and combining spherical harmonic analysis of gravity field and Green’s functions to calculate loads. Temporal and spatial analyses on the impacts are conducted with Continuously Operating Reference Stations (CORS) sites along the coast and on the islands. This paper has drawn some conclusions as follows: (1) The impact of non-tidal ocean loads on the east coastal geoid ranges from ?4.16 to 4.17mm, that on ground gravity ranges from ?15.44 to 17.02 some conclusions as follows: (1) The impact oranges from ?7.55 to 6.69mm. (2) The impacts are dominated by annual and semi-annual cycles. (3) The impacts appear to be more prominent in coastal areas and on islands than in inland areas. Numéro de notice : A2021-058 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2020.1835757 Date de publication en ligne : 06/11/2020 En ligne : https://doi.org/10.1080/01490419.2020.1835757 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96847 [article]

Illuminating the spatio-temporal evolution of the 2008–2009 Qaidam earthquake sequence with the joint use of Insar time series and teleseismic data / Simon Daout in Remote sensing, vol 12 n° 17 (September 2020)  

Public [article]  inRemote sensing > vol 12 n° 17 (September 2020) . - 23 p. Titre : Illuminating the spatio-temporal evolution of the 2008–2009 Qaidam earthquake sequence with the joint use of Insar time series and teleseismic data Type de document : Article/Communication Auteurs : Simon Daout, Auteur ; Andreas Steinberg, Auteur ; Marius Paul Isken, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 23 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse spatio-temporelle [Termes IGN] données géodésiques [Termes IGN] faille géologique [Termes IGN] image Envisat [Termes IGN] image radar moirée [Termes IGN] inférence [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] séisme [Termes IGN] série temporelle [Termes IGN] sismologie [Termes IGN] Tsinghai (Chine) Résumé : (auteur) Inferring the geometry and evolution of an earthquake sequence is crucial to understand how fault systems are segmented and interact. However, structural geological models are often poorly constrained in remote areas and fault inference is an ill-posed problem with a reliability that depends on many factors. Here, we investigate the geometry of the Mw 6.3 2008 and 2009 Qaidam earthquakes, in northeast Tibet, by combining InSAR time series and teleseismic data. We conduct a multi-array back-projection analysis from broadband teleseismic data and process three overlapping Envisat tracks covering the two earthquakes to extract the spatio-temporal evolution of seismic ruptures. We then integrate both geodetic and seismological data into a self-consistent kinematic model of the earthquake sequence. Our results constrain the depth and along-strike segmentation of the thrust-faulting sequence. The 2008 earthquake ruptured a ∼32° north-dipping fault that roots under the Olongbulak pop-up structure at ∼12 km depth and fault slip evolved post-seismically in a downdip direction. The 2009 earthquake ruptured three south-dipping high-angle thrusts and propagated from ∼9 km depth to the surface and bilaterally along the south-dipping segmented 55–75° high-angle faults of the Olonbulak pop-up structure that displace basin deformed sedimentary sequences above Paleozoic bedrock. Our analysis reveals that the inclusion of the post-seismic afterslip into modelling is beneficial in the determination of fault geometry, while teleseismic back-projection appears to be a robust tool for identifying rupture segmentation for moderate-sized earthquakes. These findings support the hypothesis that the Qilian Shan is expanding southward along a low-angle décollement that partitions the oblique convergence along multiple flower and pop-up structures. Numéro de notice : A2020-599 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.3390/rs12172850 Date de publication en ligne : 02/09/2020 En ligne : https://doi.org/10.3390/rs12172850 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95947 [article]

The direct geodesic problem and an approximate analytical solution in Cartesian coordinates on a triaxial ellipsoid / Georgios Panou in Journal of applied geodesy, vol 14 n° 2 (April 2020)  

Public [article]  inJournal of applied geodesy > vol 14 n° 2 (April 2020) . - pp 205 – 213 Titre : The direct geodesic problem and an approximate analytical solution in Cartesian coordinates on a triaxial ellipsoid Type de document : Article/Communication Auteurs : Georgios Panou, Auteur ; Romylos Korakitis, Auteur Année de publication : 2020 Article en page(s) : pp 205 – 213 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie [Termes IGN] coordonnées cartésiennes [Termes IGN] coordonnées ellipsoïdales [Termes IGN] données géodésiques [Termes IGN] ellipsoïde (géodésie) [Termes IGN] géométrie analytique [Termes IGN] série de Taylor [Termes IGN] sphèroïde [Termes IGN] transformation de coordonnées Résumé : (auteur) In this work, the direct geodesic problem in Cartesian coordinates on a triaxial ellipsoid is solved by an approximate analytical method. The parametric coordinates are used and the parametric to Cartesian coordinates conversion and vice versa are presented. The geodesic equations on a triaxial ellipsoid in Cartesian coordinates are solved using a Taylor series expansion. The solution provides the Cartesian coordinates and the angle between the line of constant v and the geodesic at the end point. An extensive data set of geodesics, previously studied with a numerical method, is used in order to validate the presented analytical method in terms of stability, accuracy and execution time. We conclude that the presented method is suitable for a triaxial ellipsoid with small eccentricities and an accurate solution is obtained. At a similar accuracy level, this method is about thirty times faster than the corresponding numerical method. Finally, the presented method can also be applied in the degenerate case of an oblate spheroid, which is extensively used in geodesy. Numéro de notice : A2020-218 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0066 Date de publication en ligne : 12/02/2020 En ligne : https://doi.org/10.1515/jag-2019-0066 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94911 [article]

Radial interpolation of GPS and leveling data of ground deformation in a resurgent caldera: application to Campi Flegrei (Italy) / Andrea Bevilacqua in Journal of geodesy, vol 94 n°2 (February 2020)  

Public [article]  inJournal of geodesy > vol 94 n°2 (February 2020) Titre : Radial interpolation of GPS and leveling data of ground deformation in a resurgent caldera: application to Campi Flegrei (Italy) Type de document : Article/Communication Auteurs : Andrea Bevilacqua, Auteur ; Augusto Neri, Auteur ; Prospero De Martino, Auteur ; et al., Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse diachronique [Termes IGN] caldeira [Termes IGN] Campanie (Italie) [Termes IGN] déformation horizontale de la croute terrestre [Termes IGN] déformation verticale de la croute terrestre [Termes IGN] donnée de nivellement [Termes IGN] données géodésiques [Termes IGN] données GPS [Termes IGN] fonction de base radiale [Termes IGN] image radar moirée [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] interpolation [Termes IGN] modèle de déformation tectonique [Termes IGN] régression linéaire [Termes IGN] réseau de nivellement [Termes IGN] surveillance géologique [Termes IGN] volcan Résumé : (auteur) This study presents a new method, called the Radial Interpolation Method, to interpolate data characterized by an approximately radial pattern around a relatively constrained central zone, such as the ground deformation patterns shown in many active volcanic areas. The method enables the fast production of short-term deformation maps on the base of spatially sparse ground deformation measurements and can provide uncertainty quantification on the interpolated values, fundamental for hazard assessment purposes and deformation source reconstruction. The presented approach is not dependent on a priori assumptions about the geometry, location and physical properties of the source, except for the requirement of a locally radial pattern, i.e., allowing multiple centers of symmetry. We test the new method on a synthetic point source example, and then, we apply the method to selected time intervals of real geodetic data collected at the Campi Flegrei caldera during the last 39 years, including examples of leveling, Geodetic Precise Traversing measurements and Global Positioning System. The maps of horizontal displacement, calculated inland, show maximum values lying along a semicircular annular region with a radius of about 2–3 km in size. This semi-annular area is marked by mesoscale structures such as faults, sand dikes and fractures. The maps of vertical displacement describe a linear relation between the maximum vertical uplift measured and the volume variation. The multiplicative factor in the linear relation is about 0.3 × 106 m3/cm if we estimate the proportion of the ΔV that is captured by the GPS network onland and we use this to estimate the full ΔV. In this case, the 95% confidence interval on K because of linear regression is ± 5%. Finally, we briefly discuss how the new method could be used for the production of short-term vent opening maps on the base of real-time geodetic measurements of the horizontal and vertical displacements. Numéro de notice : A2020-152 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01355-x Date de publication en ligne : 05/02/2020 En ligne : https://doi.org/10.1007/s00190-020-01355-x Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94785 [article]

Suivi géodésique des réservoirs souterrains / Eric Henrion (2019)  

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Identification and extraction of seasonal geodetic signals due to surface load variations / Stacy Larochelle in Journal of geophysical research : Solid Earth, vol 123 n° 12 (December 2018)  

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Assimilation de données géodésiques et estimation de références pour l’étude du changement climatique – Présentation du projet ANR GEODESIE / David Coulot in XYZ, n° 152 (septembre - novembre 2017)

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Semi-parametric segmentation of multiple series using a DP-Lasso strategy / Karine Bertin in Journal of Statistical Computation and Simulation, vol 87 n° 6 (2017)  

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A global geodetic roadmap / Matteo Luccio in xyHt, vol 2015 n° 5 (May 2015)  

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The 1st International workshop on the quality of geodetic observation and monitoring systems (QuGOMS'11) / Hansjörg Kutterer (2015)  

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Adjustment of geodetic measurements with mixed multiplicative and additive random errors / Peilang Xu in Journal of geodesy, vol 87 n° 7 (July 2013)  

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The crustal dynamics data information system: a resource to support scientific analysis using space geodesy / Carey E. Noll in Advances in space research, vol 45 n° 12 (15/06/2010)

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Homogeneous reprocessing of the EUREF permanent network : first experiences and comparisons / A. Kenyeres in Bulletin of geodesy and geomatics BGG, vol 68 n° 3 (October 2009)

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EuroSDR & ISPRS Workshop Geosensor Networks, February 20 - 22 2008, Hannover Germany / Christian Heipke (2008)  

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