Centre dedocumentation
scientifique

The use of gravity data to determine orthometric heights at the Hong Kong territories / Albertini Nsiah Ababio in Journal of applied geodesy, vol 16 n° 4 (October 2022)  

Public [article]  inJournal of applied geodesy > vol 16 n° 4 (October 2022) . - pp 401 - 416 Titre : The use of gravity data to determine orthometric heights at the Hong Kong territories Type de document : Article/Communication Auteurs : Albertini Nsiah Ababio, Auteur ; Robert Tenzer, Auteur Année de publication : 2022 Article en page(s) : pp 401 - 416 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] altitude orthométrique [Termes IGN] correction orthométrique [Termes IGN] Hong-Kong [Termes IGN] interpolation [Termes IGN] levé gravimétrique [Termes IGN] montagne [Termes IGN] système de référence local [Vedettes matières IGN] Altimétrie Résumé : (auteur) The Hong Kong Principal Datum (HKPD) is the currently adopted official geodetic vertical datum at the Hong Kong territories. The HKPD is practically realized by heights of levelling benchmarks. The HKPD heights are, however, neither normal nor orthometric. The reason is that heights of levelling benchmarks were determined from precise levelling measurements, but without involving gravity observations along levelling lines. To reduce systematic errors due to disregarding the gravity information along levelling lines, we used terrestrial and marine gravity data to interpolate gravity values at levelling benchmarks in order to compute and apply the orthometric correction to measured levelling height differences. Our results demonstrate the importance of incorporating the gravity information even for a relatively small region but characterized by a rough topography with heights of levelling benchmarks exceeding several hundreds of meters. According to our estimates, the orthometric correction reaches (and even slightly exceeds) ±2 cm, with maxima along levelling lines crossing mountain chains. Numéro de notice : A2022-742 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2022-0012 Date de publication en ligne : 04/08/2022 En ligne : https://doi.org/10.1515/jag-2022-0012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101724 [article]

Estimation of the height datum geopotential value of Hong Kong using the combined Global Geopotential Models and GNSS/levelling data / Panpan Zhang in Survey review, vol 54 n° 383 (March 2022)  

Public [article]  inSurvey review > vol 54 n° 383 (March 2022) . - pp 106 - 116 Titre : Estimation of the height datum geopotential value of Hong Kong using the combined Global Geopotential Models and GNSS/levelling data Type de document : Article/Communication Auteurs : Panpan Zhang, Auteur ; Lifeng Bao, Auteur ; Dongmei Guo, Auteur Année de publication : 2022 Article en page(s) : pp 106 - 116 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] données GNSS [Termes IGN] données GOCE [Termes IGN] données GRACE [Termes IGN] données topographiques [Termes IGN] Earth Gravity Model 2008 [Termes IGN] géoïde altimétrique [Termes IGN] Hong-Kong [Termes IGN] MNS SRTM [Termes IGN] modèle de géopotentiel local [Termes IGN] nivellement [Termes IGN] système de référence altimétrique Résumé : (auteur) The advent of the Gravity Recovery and Climate Experiment (GRACE) and Gravity field and steady-state Ocean Circulation Exploration (GOCE) has changed the global contribution in the determination of high-accuracy global geopotential models (GGMs). In this paper, a spectral expansion method is used to determine the combined GGMs, using the high-resolution EGM2008 model and residual terrain model (RTM) to effectively bridge the spectral gap between the satellite and terrestrial data. The accuracy of the combined GGMs shows improvement compared with GOCE/GRACE-based GGMs and EGM2008 in determining the geopotential of the Hong Kong Principal Datum (HKPD). As a result of the DIR_R5/EGM2008/RTM model and GNSS/levelling, the geopotential value of HKPD is estimated to be 62,636,860.52 m2s−2 with respect to the global geoid W0 = 62,636,853.4 m2s−2. Therefore, the vertical offset between the HKPD and global geoid is about −72.8 cm, which means that the HKPD is 72.8 cm below the global height datum. Numéro de notice : A2022-238 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2021.1884794 Date de publication en ligne : 17/02/2021 En ligne : https://doi.org/10.1080/00396265.2021.1884794 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100162 [article]

Complexity-based matching between image resolution and map scale for multiscale image-map generation / Qian Peng in International journal of geographical information science IJGIS, vol 35 n° 10 (October 2021)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 35 n° 10 (October 2021) . - pp 1951 - 1974 Titre : Complexity-based matching between image resolution and map scale for multiscale image-map generation Type de document : Article/Communication Auteurs : Qian Peng, Auteur ; Zhilin Li, Auteur ; Jun Chen, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 1951 - 1974 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] appariement de lignes [Termes IGN] échelle cartographique [Termes IGN] Hong-Kong [Termes IGN] niveau de détail [Termes IGN] objet géographique linéaire [Termes IGN] orthophotocarte [Termes IGN] précision cartographique [Termes IGN] précision planimétrique [Termes IGN] résolution globale (imagerie) [Termes IGN] symbole graphique [Termes IGN] visualisation multiéchelle [Vedettes matières IGN] Généralisation Résumé : (auteur) An image-map is a compromise between an image and a map. The quality of such maps is affected by several factors, such as (a) the matching between the features on images and the graphic symbols from maps, (b) the complexity of background images, and (c) the representation of graphic and text symbols on the images. This project deals with the first issue. The current solution is that the accuracy of images should satisfy the accuracy standard of maps. However, images with different resolutions can satisfy the standard for a specific map scale. This may lead to a situation in which the levels of detail (LoD) in images may not match the complexity of map features although the planimetric accuracy is matched. To solve this problem, we developed a complexity-based matching between the image resolution and map scale. More precisely, the matching is based on the complexity of line features. Experimental evaluations were conducted in 15 representative areas in Hong Kong using maps at seven scales and eight image resolutions. Results show that the proposed complexity-based method is capable of obtaining good matching between image resolution and map scale in terms of both accuracy and users’ preference. Numéro de notice : A2021-655 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2021.1885674 Date de publication en ligne : 12/04/2021 En ligne : https://doi.org/10.1080/13658816.2021.1885674 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98391 [article]

RegNet: a neural network model for predicting regional desirability with VGI data / Wenzhong Shi in International journal of geographical information science IJGIS, vol 35 n° 1 (January 2021)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 35 n° 1 (January 2021) . - pp 175 - 192 Titre : RegNet: a neural network model for predicting regional desirability with VGI data Type de document : Article/Communication Auteurs : Wenzhong Shi, Auteur ; Zhewei Liu, Auteur ; Zhenlin An, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 175 - 192 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] classification par réseau neuronal [Termes IGN] données localisées des bénévoles [Termes IGN] Hong-Kong [Termes IGN] modèle de simulation [Termes IGN] niveau local [Termes IGN] participation du public [Termes IGN] régression [Termes IGN] réseau social géodépendant Résumé : (auteur) Volunteered geographic information can be used to predict regional desirability. A common challenge regarding previous works is that intuitive empirical models, which are inaccurate and bring in perceptual bias, are traditionally used to predict regional desirability. This results from the fact that the hidden interactions between user online check-ins and regional desirability have not been revealed and clearly modelled yet. To solve the problem, a novel neural network model ‘RegNet’ is proposed. The user check-in history is input into a neural network encoder structure firstly for redundancy reduction and feature learning. The encoded representation is then fed into a hidden-layer structure and the regional desirability is predicted. The proposed RegNet is data-driven and can adaptively model the unknown mappings from input to output, without presumed bias and prior knowledge. We conduct experiments with real-world datasets and demonstrate RegNet outperforms state-of-the-art methods in terms of ranking quality and prediction accuracy of rating. Additionally, we also examine how the structure of encoder affects RegNet performance and suggest on choosing proper sizes of encoded representation. This work demonstrates the effectiveness of data-driven methods in modelling the hidden unknown relationships and achieving a better performance over traditional empirical methods. Numéro de notice : A2021-023 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2020.1768261 Date de publication en ligne : 18/05/2020 En ligne : https://doi.org/10.1080/13658816.2020.1768261 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96526 [article]

Réservation

Réserver ce document

Exemplaires (2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2021011	SL	Revue	Centre de documentation	Revues en salle	Disponible
079-2021012	SL	Revue	Centre de documentation	Revues en salle	Disponible

Automated labeling of schematic maps by optimization with knowledge acquired from existing maps / Tian Lan in Transactions in GIS, Vol 24 n° 6 (December 2020)  

Public [article]  inTransactions in GIS > Vol 24 n° 6 (December 2020) . - pp 1722 - 1739 Titre : Automated labeling of schematic maps by optimization with knowledge acquired from existing maps Type de document : Article/Communication Auteurs : Tian Lan, Auteur ; Zhilin Li, Auteur ; Qian Peng, Auteur ; Xinyu Gong, Auteur Année de publication : 2020 Article en page(s) : pp 1722 - 1739 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] automatisation [Termes IGN] calcul d'itinéraire [Termes IGN] Chine [Termes IGN] données cartographiques [Termes IGN] Hong-Kong [Termes IGN] optimisation (mathématiques) [Termes IGN] réseau métropolitain [Termes IGN] segmentation sémantique Résumé : (Auteur) Schematic maps are simplified representations of line networks, aiming to help people quickly and accurately perform route planning and orientation tasks. The automated generation of such maps is generally treated as an optimization problem. Most researchers prefer to optimize network layouts and name labels separately, because optimizing them simultaneously is still intractable. It is found that optimizing network layouts is extensively studied, while optimizing name labels is rarely considered. In the optimization of name labels, constraints can be established with rules from cartographic experts, literature (e.g., specification and technical documents), and/or existing maps. However, some rules from experts and literature cannot be explicitly and mathematically expressed. This study aims to develop an automated labeling method with rules from existing maps. We first acquire the rules (i.e., the potential positions and the preferences of these positions) from some existing schematic maps and then integrate them into an optimization algorithm. Experimental evaluation is conducted by a questionnaire in terms of “ease level of finding name labels,” “congestion level,” and “satisfaction level” using Tianjin and Hong Kong metro schematic maps and the labels of our method. The results show that the proposed method can automatically generate effective labels. Numéro de notice : A2020-769 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12671 Date de publication en ligne : 06/08/2020 En ligne : https://doi.org/10.1111/tgis.12671 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96661 [article]

An empirical study on the intra-urban goods movement patterns using logistics big data / Pengxiang Zhao in International journal of geographical information science IJGIS, vol 34 n° 6 (June 2020)  

Permalink

Estuaries and coastal zones / Jiayi Pan (2020)  

Permalink

Novel adaptive histogram trend similarity approach for land cover change detection by using bitemporal very-high-resolution remote sensing images / Zhi Yong Lv in IEEE Transactions on geoscience and remote sensing, vol 57 n° 12 (December 2019)  

Permalink

Comparison between convolutional neural networks and random forest for local climate zone classification in mega urban areas using Landsat images / Cheolhee Yoo in ISPRS Journal of photogrammetry and remote sensing, vol 157 (November 2019)  

Permalink

Structural segmentation and classification of mobile laser scanning point clouds with large variations in point density / Yuan Li in ISPRS Journal of photogrammetry and remote sensing, vol 153 (July 2019)  

Permalink

Integration of aerial oblique imagery and terrestrial imagery for optimized 3D modeling in urban areas / Bo Wu in ISPRS Journal of photogrammetry and remote sensing, vol 139 (May 2018)  

Permalink

A new scheme for urban impervious surface classification from SAR images / Hongsheng Zhang in ISPRS Journal of photogrammetry and remote sensing, vol 139 (May 2018)  

Permalink

Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong / Wu Zhu in Advances in space research, vol 58 n° 4 (August 2016)  

Permalink

Empirical determination of geometric parameters for selective omission in a road network / Qi Zhou in International journal of geographical information science IJGIS, vol 30 n° 1-2 (January - February 2016)  

Permalink

Geometric integration of high-resolution satellite imagery and airborne LiDAR data for improved geopositioning accuracy in metropolitan areas / Bo Wu in ISPRS Journal of photogrammetry and remote sensing, vol 109 (November 2015)  

Permalink