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Method for an automatic alignment of imagery and vector data applied to cadastral information in Poland / Juan J. Ruiz-Lendínez in Survey review, vol 51 n° 365 (March 2019)  

Public [article]  inSurvey review > vol 51 n° 365 (March 2019) . - pp 123 - 134 Titre : Method for an automatic alignment of imagery and vector data applied to cadastral information in Poland Type de document : Article/Communication Auteurs : Juan J. Ruiz-Lendínez, Auteur ; B. Maćkiewicz, Auteur ; P. Motek, Auteur ; T. Stryjakiewicz, Auteur Année de publication : 2019 Article en page(s) : pp 123 - 134 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] carrefour [Termes IGN] conflation [Termes IGN] données cadastrales [Termes IGN] données vectorielles [Termes IGN] incertitude géométrique [Termes IGN] limite cadastrale [Termes IGN] orthoimage [Termes IGN] Pologne [Termes IGN] segmentation d'image [Termes IGN] texture d'image Résumé : (Auteur) Nowadays, an important problem in combining vector data and imagery is that they rarely align. This problem can become particularly acute in the case of cadastral systems. In this study, and as part of the partnership between the Universities of Jaén and Adam Mickiewicz (Poznań), we provide a methodological proposal to assess the conflation procedures between cadastral vector data and imagery, improving the alignment between both data sets. To do this, we use an automatic alignment algorithm which detects road intersections from both data sets as control points by using image texture characterisation. With this method, we first train the system on the imagery to learn the road texture distribution, then we can obtain its segmentation according to its texture, and finally the system locates road intersection points. The last step is to align vector data and imagery by using different techniques. This algorithm is based on an earlier one, detailed in [Ruiz, J.J., Rubio, T.J., and Ureña, M.A., 2011b. Automatic extraction of road intersections from images in conflation processes based on texture characterization. Survey review, 43 (321), 212–225.]. However, in the updated version we have solved the problem of not-well-defined intersection points, resulting in a substantial increase in the number of intersection points employed for the final adjustment to align both products and in a reduction of the computation time. On the other hand, the positional uncertainty assessment of parcel boundary lines both before and after applying our alignment procedure between them is provided. With regard to the experimental results, in the case of Polish cadastral data this procedure allows for significant improvement in the alignment between imagery and cadastral parcels boundaries. Numéro de notice : A2019-189 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1388959 Date de publication en ligne : 20/10/2017 En ligne : https://doi.org/10.1080/00396265.2017.1388959 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92626 [article]

Analysis of ocean tide loading displacements by GPS kinematic precise point positioning: a case study at the China coastal site SHAO / H. Zhao in Survey review, vol 51 n° 365 (March 2019)  

Public [article]  inSurvey review > vol 51 n° 365 (March 2019) . - pp 172 - 182 Titre : Analysis of ocean tide loading displacements by GPS kinematic precise point positioning: a case study at the China coastal site SHAO Type de document : Article/Communication Auteurs : H. Zhao, Auteur ; Q. Zhang, Auteur ; R. Tu, Auteur ; Z. Liu, Auteur Année de publication : 2019 Article en page(s) : pp 172 - 182 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse spectrale [Termes IGN] Chine [Termes IGN] données GPS [Termes IGN] données marégraphiques [Termes IGN] GPS en mode cinématique [Termes IGN] littoral [Termes IGN] marée océanique [Termes IGN] positionnement ponctuel précis [Termes IGN] série temporelle [Termes IGN] surcharge océanique Résumé : (Auteur) Ocean tide loading (OTL) displacement amplitudes and phase lags of SHAO site are estimated by global positioning system (GPS), kinematic precise point positioning (PPP) and spectral analysis using 19 years of continuous GPS observations. In kinematic PPP, the 66 additional harmonic displacement parameters are replaced by the three time-varying displacement parameters without a priori modelled OTL displacements. By comparing the results with predictions from hybrid regional/global models, we are able to demonstrate that GPS/model agreements are at the level of 0.2 mm (horizontal) and 0.6 mm (vertical) for the four lunar constituents, 0.4 mm (horizontal) and 1.35 mm (vertical) for the four solar/sidereal constituents, and 0.2 mm (horizontal) and 0.3 mm (vertical) for the three long-period constituents. Finally, we conclude that GPS-derived lunar constituents can substitute for the model corrections in GPS data processing and the accuracy of GPS-derived solar/sidereal constituents needs to be improved by further studies. Numéro de notice : A2019-190 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1407392 Date de publication en ligne : 30/11/2017 En ligne : https://doi.org/10.1080/00396265.2017.1407392 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92634 [article]

Impact of predicting real-time clock corrections during their outages on precise point positioning / Ahmed El-Mowafy in Survey review, vol 51 n° 365 (March 2019)  

Public [article]  inSurvey review > vol 51 n° 365 (March 2019) . - pp 183 - 192 Titre : Impact of predicting real-time clock corrections during their outages on precise point positioning Type de document : Article/Communication Auteurs : Ahmed El-Mowafy, Auteur Année de publication : 2019 Article en page(s) : pp 183 - 192 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] décalage d'horloge [Termes IGN] données GNSS [Termes IGN] orbite [Termes IGN] positionnement ponctuel précis [Termes IGN] temps réel Résumé : (Auteur) Real-time precise point positioning (RT-PPP) is a popular positioning method for natural hazard warning systems (NHWS) such as for monitoring tsunami and earthquakes. PPP relays on the use of precise orbits and clock corrections. Hence, the positioning accuracy of RT-PPP will significantly deteriorate when experiencing a discontinuity in receiving these corrections, for instance due to a temporary modem failure. The best available approach in this case would be to use the International Global Navigation Satellite Systems Service ultra-rapid (IGU) orbits and clocks that would result in a low positioning accuracy. In this paper, we present a simplified approach to a method that we recently proposed to bridge outages in the corrections and improve the RT-PPP accuracy compared with the use of IGU. In this method, the most recent IGU orbits are used as they are compatible with the RT orbits; however, the clock corrections are predicted as a time series using a linear model with four sinusoidal terms. The prediction errors resulting from this method, age of the model and its validity period are discussed. The impact of using the proposed approach is evaluated at a number of sites of known positions by comparing its performance to using IGU orbits and clocks. Moreover, the impact of using predicted corrections is assessed in different scenarios. The experimental results proved validity of the presented approach where positioning mean RMSE of less than 20 cm was maintained during the outage period. Numéro de notice : A2019-191 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1405155 Date de publication en ligne : 26/11/2017 En ligne : https://doi.org/10.1080/00396265.2017.1405155 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92635 [article]