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Generalization of DEM for terrain analysis using a compound method / Q. Zhou in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 1 (January - February 2011)
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Titre : Generalization of DEM for terrain analysis using a compound method Type de document : Article/Communication Auteurs : Q. Zhou, Auteur ; Y. Chen, Auteur Année de publication : 2011 Article en page(s) : pp 38 - 45 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] erreur moyenne quadratique
[Termes IGN] généralisation automatique de données
[Termes IGN] généralisation de MNT
[Termes IGN] modèle numérique de surface
[Termes IGN] Triangulated Irregular NetworkRésumé : (Auteur) This paper reports an investigation into the generalization of a grid-based digital elevation model (DEM) for the purpose of terrain analysis. The focus is on the method of restructuring the grid-based surface elevation data to form a triangulated irregular network (TIN) that is optimized to keep the important terrain features and slope morphology with the minimum number of sample points. The critical points of the terrain surface are extracted from the DEM based on their significance, measured not only by their local relief, but also by their importance in identifying inherent geomorphological and drainage features in the DEM. A compound method is proposed by integrating the traditional point-additive and feature-point methods to construct a drainage-constrained TIN. The outcome is then compared with those derived from other selected methods including filtering, point-additive or feature-point algorithms. The results show that the compound approach is capable of taking advantage of both point-additive and feature-point algorithms to maximally keep the terrain features and to maintain RMSE at an acceptable level, while reducing the elevation data points by over 99%. The analytical result also shows that the proposed method outperforms the compared methods with better control in retaining drainage features at the same level of RMSE. Numéro de notice : A2011-015 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.08.005 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.08.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30797
in ISPRS Journal of photogrammetry and remote sensing > vol 66 n° 1 (January - February 2011) . - pp 38 - 45[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2011011 SL Revue Centre de documentation Revues en salle Disponible Orthorectification of VHR optical satellite data exploiting the geometric accuracy of TerraSAR-X data / Peter Reinartz in ISPRS Journal of photogrammetry and remote sensing, vol 66 n° 1 (January - February 2011)
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Titre : Orthorectification of VHR optical satellite data exploiting the geometric accuracy of TerraSAR-X data Type de document : Article/Communication Auteurs : Peter Reinartz, Auteur ; R. Muller, Auteur ; P. Schwind, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 124 - 132 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image mixte
[Termes IGN] appariement d'images
[Termes IGN] erreur moyenne quadratique
[Termes IGN] image ALOS-PRISM
[Termes IGN] image Ikonos
[Termes IGN] image optique
[Termes IGN] image radar
[Termes IGN] image TerraSAR-X
[Termes IGN] méthode robuste
[Termes IGN] modèle par fonctions rationnelles
[Termes IGN] orientation du capteur
[Termes IGN] orthorectification
[Termes IGN] point d'appui
[Termes IGN] précision géométrique (imagerie)
[Termes IGN] zone urbaineRésumé : (Auteur) Orthorectification of satellite data is one of the most important pre-processing steps for application oriented evaluations and for image data input into Geographic Information Systems. Although high- and very high-resolution optical data can be rectified without ground control points (GCPs) using an underlying digital elevation model (DEM) to positional root mean square errors (RMSEs) between 3 m and several hundred meters (depending on the satellite), there is still need for ground control with higher precision to reach lower RMSE values for the orthoimages. The very high geometric accuracy of geocoded data of the TerraSAR-X satellite has been shown in several investigations. This is due to the fact that the SAR antenna measures distances which are mainly dependent on the terrain height and the position of the satellite. The latter can be measured with high precision, whereas the satellite attitude need not be known exactly. If the used DEM is of high accuracy, the resulting geocoded SAR data are very precise in their geolocation. This precision can be exploited to improve the orientation knowledge and thereby the geometric accuracy of the rectified optical satellite data. The challenge is to match two kinds of image data, which exhibit very different geometric and radiometric properties. Simple correlation techniques do not work and the goal is to develop a robust method which works even for urban areas, including radar shadows, layover and foreshortening effects. First the optical data have to be rectified with the available interior and exterior orientation data or using rational polynomial coefficients (RPCs). From this approximation, the technique used is the measurement of small identical areas in the optical and radar images by automatic image matching, using a newly developed adapted mutual information procedure followed by an estimation of correction terms for the exterior orientation or the RPC coefficients. The matching areas are selected randomly from a regular grid covering the whole imagery. By adjustment calculations, parameters from falsely matched areas can be eliminated and optimal improvement parameters are found. The original optical data are orthorectified again using the delivered metadata together with these corrections and the available DEM. As proof of method the orthorectified data from IKONOS and ALOS-PRISM sensors are compared with conventional ground control information from high-precision orthoimage maps of the German Cartographic Survey. The results show that this method is robust, even for urban areas. Although the resulting RMSE values are in the order of 2–6 m, the advantage is that this result can be reached even for optical sensors which do not exhibit low RMSE values without using manual GCP measurements. Numéro de notice : A2011-017 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2010.10.003 En ligne : https://doi.org/10.1016/j.isprsjprs.2010.10.003 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30799
in ISPRS Journal of photogrammetry and remote sensing > vol 66 n° 1 (January - February 2011) . - pp 124 - 132[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2011011 SL Revue Centre de documentation Revues en salle Disponible
Titre : Sub-daily parameter estimation in VLBI data analysis : Dissertation carried out in order to obtain the academic degree ”doctor of the technical sciences” under the supervision of o.Univ.-Prof. Dipl.-Ing. Dr.techn. Harald Schuh, presented at the Vienna University of Technology, Faculty of Mathematics and Geoinformation, Institute of Geodesy and Geophysics Type de document : Thèse/HDR Auteurs : Kamil Teke, Auteur ; Harald Schuh, Directeur de thèse Editeur : Vienne [Autriche] : Vienna University of Technology Année de publication : 2011 Importance : 275 p. Format : 21 x 30 cm Note générale : Bibliographie
thèse étrangèreLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] compensation par moindres carrés
[Termes IGN] données ITGB
[Termes IGN] estimation des paramètres
[Termes IGN] estimation statistique
[Termes IGN] horloge
[Termes IGN] propagation troposphérique
[Termes IGN] rotation de la TerreIndex. décimale : THESE Thèses et HDR Résumé : (Auteur) The main objective of the work carried out within the scope of this thesis is the contribution to the VLBI2010 project of the International Very Long Baseline Interferometry (VLBI) Service for Geodesy and Astrometry (IVS) by means of developing a parameter estimation module (vie lsm) of Vienna VLBI Software (VieVS) which is capable of estimating accurate sub-daily VLBI geodetic parameters. The vie lsm module is based on the classical Gauss Markoff Least-Squares (LS) adjustment method by using continuous piece-wise linear offset (CPWLO) functions which are estimated at unique epochs, e.g. at integer hours, or at integer fractions or integer multiples of integer hours. The interval for CPWLO modelling of the parameters is usually set to values between one day to five minutes.
To investigate the sub-daily tidal motions of the VLBI antennas during IVS-CONT05, hourly CPWLO Terrestrial Reference Frame (TRF) coordinates of the antennas were estimated. Although all tidal displacements are computed from state-of-the-art geophysical models and reduced from the observations a priori to the adjustment, the radial amplitudes from the estimated hourly antenna coordinates can reach up to 1 cm (Kokee, HartRAO, Gilcreek, Westford, Svetloe, and Wettzell). To analyze the high frequency (sub-daily) Earth rotation parameter (HF-ERP) estimates of VieVS during IVS-CONT08, hourly CPWLO ERP were estimated. The Fourier spectra of the hourly VLBI and Global Positioning System (GPS) ERP estimates and the HFERP models during IVS-CONT08 are in a good agreement at prograde and retrograde 12 hours both for length of day (LOD) and polar motion. However, at 24 hour prograde polar motion the amplitude from GPS is larger by about 100 ìas than VLBI and larger by about 160 ìas than HF-ERP models. Additionally, VieVS LOD and polar motion estimates are noisier than from GPS. This may be due to the fact that no relative constraints between the CPWLO ERP estimates in VLBI analysis were introduced. The estimation of hourly source coordinates was rather intended as test study. As long as hourly CPWLO coordinates of two sources are estimated and the remaining sources are fixed to their a priori Celestial Reference Frame (CRF) i coordinates, parametrization of the Earth Orientation Parameters (EOP) is not critical for the estimated source coordinates. However, investigations on this issue need to be carried out in future, e.g. a lot can be learned from correlations between hourly source coordinates and the observation geometry.
The second aim of this thesis, which is also a very good test of the CPWLO estimates of troposphere zenith delays and gradients, is the contribution to combination studies in the framework of the Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) by multi-technique comparison of zenith total delays (ZTD) and troposphere gradients. In the scope of this issue, VLBI VieVS estimates of troposphere ZTD and gradients during IVS-CONT08 were compared with those derived from observations with the GPS, Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), and water vapor radiometers (WVR) co-located with the VLBI radio telescopes. ZTD and gradients estimated by space geodetic techniques are compared to those computed by ray-tracing through the profiles of various Numerical Weather Models (NWM), such as the European Centre for Medium-Range Weather Forecasts (ECMWF) (all sites), the Japan Meteorological Agency (JMA) and Cloud Resolving Storm Simulator (CReSS) (Tsukuba in Japan), and the High Resolution Limited Area Model (HIRLAM) (European sites). The best inter space geodetic technique agreement of ZTD during IVS-CONT08 is found between the combined IVS and the International GNSS Service (IGS) solutions with a mean standard deviation of about 6 mm over all sites, whereas the agreement with numerical weather models is between 6 and 20 mm. The standard deviations are generally larger at low latitude sites because of higher humidity, and the latter is also the reason why the standard deviations are larger at northern hemisphere stations during IVS-CONT08 in comparison to IVS-CONT02 which was observed in October 2002. The assessment of the troposphere gradients from the different techniques is not as clear because of different time intervals, different estimation properties, or different observable. However, the best inter-technique agreement is found between the IVS combined gradients and the GPS solutions with standard deviations between 0.2 mm and 0.7 mm. As mentioned before all the comparisons and validation tests on the troposphere products during IVS-CONT08 presented in this thesis provide important information with respect to the planned combination and integration of various observing techniques in the framework of the Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG).Note de contenu : 1 Introduction
1.1 VLBI Basics
1.2 Contribution of the thesis and research objectives
1.3 Outline of the thesis
2 VLBI delay model
2.1 Gravitational delay
2.2 Vacuum delay and geometric delay
2.3 Partial derivatives of the VLBI delay model with respect to EOP, antenna and source coordinates
2.4 Continuous piece-wise linear offset (CPWLO) functions for sub-daily parameter estimation
3 Least Squares (LS) Adjustment
3.1 Gauss Markoff model
3.2 Constraining parameters
3.3 Free Network Solution
3.4 Stacking normal equation systems
3.5 Parameter estimation in vie lsm
3.5.1 Handling outliers
4 VLBI clock error
4.1 Modelling and estimating VLBI clock errors based on CPWLO functions
4.1.1 Clock error model
4.1.2 Determining and modelling clock breaks
4.1.3 Clock break error on the VLBI observations and its propagation on estimated VLBI parameters
4.2 Frequency stabilities of the VLBI clocks
5 Troposphere delay
5.1 Troposphere mapping functions
5.2 Troposphere gradients
5.3 Troposphere delays in VieVS
6 Multi-technique comparison of troposphere zenith delays and gradients during IVSCONT
6.1 IVS-CONT08 co-located sites, techniques and solutions
6.1.1 Space geodetic solutions
6.1.2 Water Vapor Radiometer (WVR)
6.1.3 Numerical Weather Models (NWM)
6.2 Agreement criteria for the comparisons and troposphere ties
6.3 Intra-technique comparisons of ZTD
6.4 Inter-technique comparisons of ZTD
6.5 Comparison with IVS-CONT02
6.6 Troposphere gradients comparisons
7 VLBI Baseline Length Repeatability Tests of IVS-R1 and -R4 Sessions
7.1 IVS-R1 and -R4 sessions
7.2 Comparison of baseline length repeatabilities derived from different mapping functions and cut-off angles
8 Analyses of the TRF, EOP, and CRF VLBI estimates
8.1 Analysis of the tidal motions at VLBI antennas: Sub-daily CPWLO coordinate estimates versus tide models during IVS-CONT05
8.2 Analyses of the sub-daily ERP during IVS-CONT08: model versus observations
8.3 Analyses of the sub-daily coordinate time series of several defining sources in ICRF2 during IVS-CONT08
9 Conclusions and OutlookNuméro de notice : 14249 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : sans En ligne : https://repositum.tuwien.at/handle/20.500.12708/982 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62653 The water vapour intercomparison effort in the framework of the Convective and Orographically-induced Precipitation Study: airborne-to-ground-based and airborne-to-airborne lidar systems / Rohini Bhawar in Quarterly Journal of the Royal Meteorological Society, vol 137 n° S1 (January 2011)
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Titre : The water vapour intercomparison effort in the framework of the Convective and Orographically-induced Precipitation Study: airborne-to-ground-based and airborne-to-airborne lidar systems Type de document : Article/Communication Auteurs : Rohini Bhawar, Auteur ; Paolo Di Girolamo, Auteur ; Donato Summa, Auteur ; Cyrille Flamant, Auteur ; Dietrich Althausen, Auteur ; C. Kiemle, Auteur ; Pierre Bosser , Auteur ; et al., Auteur
Année de publication : 2011 Article en page(s) : pp 325 - 348 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] coordonnées GPS
[Termes IGN] données météorologiques
[Termes IGN] erreur systématique
[Termes IGN] estimation statistique
[Termes IGN] lidar atmosphérique
[Termes IGN] lidar Raman
[Termes IGN] précipitation
[Termes IGN] vapeur d'eauRésumé : (auteur) An intensive water vapour intercomparison effort, involving airborne and ground‐based water vapour lidar systems, was carried out in the framework of the COPS experiment. The main objective of this paper is to provide accurate error estimates for these systems. Comparisons between the ground‐based Raman lidar BASIL and the airborne CNRS DIAL (Differential Absorption Lidar) indicate a mean relative bias between the two sensors, calculated with respect to the mean value of −2.13% (−0.034 g kg−1) in the altitude region 0.5–3.5 km, while comparisons between BASIL and the airborne DLR DIAL lead to a mean relative bias of 1.87% (0.018 g kg−1) in this same altitude region. Comparisons between the ground‐based UHOH DIAL and the CNRS DIAL indicate a bias of −3.2% (−0.37 × 1022 m−3) in the altitude range 1.5–4.5 km, while comparisons between the UHOH DIAL and the DLR DIAL indicate a bias of 0.83% (0.06 × 1022 m−3) in this same altitude range. Based on the available comparisons between the ground‐based Raman lidar BERTHA and the CNRS DIAL, the mean relative bias is found to be −4.37% (−0.123 g kg−1) in the altitude region 0.5–4.5 km. Comparisons between the ground‐based IGN Raman lidar and the CNRS DIAL indicate a bias of 3.18% (0.55 g kg−1) in the altitude range from 0.5 to 4.5 km, while comparisons between the CNRS DIAL and DLR DIAL result in a mean relative bias of 3.93% (1.1 × 1022 m−3) in the altitude interval 0.5–4.0 km. Based on the available statistics of comparisons, benefiting from the fact that the CNRS DIAL was able to be compared with all other lidar systems, and putting equal weight on the data reliability of each instrument, overall relative values for BASIL, BERTHA, IGN Raman lidar, UHOH DIAL, DLR DIAL, and CNRS DIAL, with respect to the mean value, are found to be −0.38, −2.60, 4.90, −1.43, −2.23 and 1.72%, respectively. Numéro de notice : A2011-601 Affiliation des auteurs : LOEMI+Ext (1985-2011) Thématique : POSITIONNEMENT Nature : Article DOI : 10.1002/qj.697 Date de publication en ligne : 06/01/2011 En ligne : https://doi.org/10.1002/qj.697 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91674
in Quarterly Journal of the Royal Meteorological Society > vol 137 n° S1 (January 2011) . - pp 325 - 348[article]
Titre : Topographie opérationnelle : mesures, calculs, dessins, implantations Type de document : Guide/Manuel Auteurs : Michel Brabant, Auteur ; Béatrice Patizel, Collaborateur ; Armelle Piègle, Collaborateur ; Hélène Müller, Collaborateur Mention d'édition : 3e édition Editeur : Paris : Eyrolles Année de publication : 2011 Collection : Blanche BTP Importance : 396 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-2-212-12847-5 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Topographie
[Termes IGN] carte Top 25
[Termes IGN] dessin cartographique
[Termes IGN] erreur systématique
[Termes IGN] implantation d'un objet
[Termes IGN] levé à grande échelle
[Termes IGN] lever des détails
[Termes IGN] lever souterrain
[Termes IGN] lever tachéométrique
[Termes IGN] mesurage d'angles
[Termes IGN] mesurage de distances
[Termes IGN] nivellement direct
[Termes IGN] nivellement indirect
[Termes IGN] plan
[Termes IGN] positionnement par GNSS
[Termes IGN] précision des mesures
[Termes IGN] système de coordonnées
[Termes IGN] système de référence géodésique
[Termes IGN] théodoliteIndex. décimale : 32.00 Topographie - généralités Résumé : (Editeur) Dans ce nouveau manuel volontairement opérationnel et abondamment illustré, on trouvera notamment la description précise des instruments de mesure et un exposé détaillé des méthodes de travail, avec calculs, dessins et techniques d'implantation. Destiné à la formation des topographes, il permettra aussi aux praticiens confirmés, de l'opérateur à l'ingénieur, d'actualiser leurs connaissances. Note de contenu : - Connaissances de base
- Mesures des angles
- Mesures des distances
- Nivellement
- Localisation terrestre
- Positionnement satellitaire
- Levé des détails et implantations
- Travaux topographiques spécifiques
- Calculs topométriques
- Dessins et plansNuméro de notice : 20572 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Manuel Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=46817 Réservation
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