Descripteur
Documents disponibles dans cette catégorie (179)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Seasonal variations of vertical crustal motion in Australia observed by joint analysis of GPS and GRACE / Hao Wang in Geomatics and Information Science of Wuhan University, vol 47 n° 2 (February 2022)
[article]
Titre : Seasonal variations of vertical crustal motion in Australia observed by joint analysis of GPS and GRACE Type de document : Article/Communication Auteurs : Hao Wang, Auteur ; Jianping Yue, Auteur ; Yunfei Xiang, Auteur Année de publication : 2022 Article en page(s) : pp 197 - 207 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse de spectre singulier
[Termes IGN] Australie
[Termes IGN] déformation verticale de la croute terrestre
[Termes IGN] données GPS
[Termes IGN] données GRACE
[Termes IGN] transformation en ondelettes
[Termes IGN] variation saisonnièreRésumé : (auteur) Objectives There are obvious seasonal variations in the GPS height time series, which affect the improvement of precision and can be corrected by both mathematical modelling and geophysical mechanisms. Compared to least square fitting, singular spectrum analysis (SSA) can extract random seasonal signals effectively through signal reconstruction, which is unaffected by the assumed sinusoidal waves. According to the elastic loading theory, the gravity recovery and climate experiment (GRACE) can be used to calculate the vertical surface displacement caused by changes in terrestrial water storage. Methods This paper mainly studies the feasibility of correcting the seasonal variations in GPS heights using SSA and GRACE inversion results. The height time series of 27 GPS stations in Australia with a time span of from 5 to 10 years were chosen and combined with GRACE simultaneous inversions. Results Because the spatial resolutions of GRACE are coarse and the loading displacement is much more sensitive to near-field mass changes than far-field ones, the amplitudes of GRACE-inferred hydrological loading deformations are significantly smaller than GPS. The weighted root mean square (WRMS) are reduced at 22 stations after GRACE-inferred displacement corrections, and the correlation coefficients between deformations estimated by GPS and GRACE range from 0.12 to 0.78 with a mean value of 0.43, indicating that GPS and GRACE results have good consistency and correlation. SSA is used to extract the annual signals of vertical displacements derived from GPS and GRACE, and contribution rates of singular spectral variance of annual signals are 21.60% and 34.48%, respectively, expressing that annual signals are the main components of GRACE-inferred results. Geographical climatic conditions have a significant impact on the consistency of annual signals derived from GPS and GRACE. Compared with the arid areas in central and western Australia, the amplitude and phase of annual signals derived from GPS and GRACE are more consistent in the northern region with seasonal rainfall. Furthermore, cross wavelet transform (XWT) finds that the vertical displacement series derived from GPS and GRACE of each station have a significant resonance period of one year. The circular average phase angles of GPS/GRACE at the period closet to 1 cycle per year (cpy) outside the cone of influence range from -74.03° to 67.23°. The mean XWT-based semblances range from 0.28 to 0.99 with an average value of 0.79, showing that there is a significant positive correlation between the annual variations derived from GPS and GRACE. Conclusions Overall, GRACE-inferred deformations can explain the annual variations of GPS-derived displacements, particularly in areas with high hydrological loading. It is possible to correct the annual signals of GPS heights by GRACE inversions, but the effect is not as good as the SSA-filtered annual signals. Numéro de notice : A2022-150 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.13203/j.whugis20190282 Date de publication en ligne : 05/02/2022 En ligne : http://dx.doi.org/10.13203/j.whugis20190282 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100109
in Geomatics and Information Science of Wuhan University > vol 47 n° 2 (February 2022) . - pp 197 - 207[article]Adaptation of the standardized vegetation optical depth index for satellite-based soil moisture / Juliette Raabe (2022)
Titre : Adaptation of the standardized vegetation optical depth index for satellite-based soil moisture Type de document : Mémoire Auteurs : Juliette Raabe, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2022 Importance : 61 p. Format : 21 x 30 cm Note générale : Bibliographie
Rapport de projet pluridisciplinaire, cycle ING2Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Australie
[Termes IGN] changement climatique
[Termes IGN] humidité du sol
[Termes IGN] implémentation (informatique)
[Termes IGN] indice d'humidité
[Termes IGN] phénomène climatique extrême
[Termes IGN] sécheresse
[Termes IGN] teneur en eau de la végétationIndex. décimale : PROJET Mémoires : Rapports de projet - stage des ingénieurs de 2e année Résumé : (Auteur) Le groupe de recherche sur la télédétection pour l’étude de l’environnement et du climat (CLIMERS) de l’université technique de Vienne contribue entre autres au développement de jeux de données d’humidité du sol (indicateur mesurant la quantité d’eau contenue dans le sol) et de VOD (vegetation optical depth, mesurant la teneur en eau des plantes). Par là, il vise à aider la communauté scientifique mondiale pour étudier le climat et en particulier, le changement climatique. L’étude présente se propose de participer à cet objectif en créant un indice de sécheresse à partir de données d’humidité du sol obtenues par télédétection. Pour ce faire, cette étude adapte un processus existant pour construire un indice de sécheresse standardisé. Ce processus a été implémenté au CLIMERS, il y a peu de temps, pour le VOD et le but est de le tester pour l’humidité du sol et voir à quel point il est adapté pour capturer des événements climatiques extrêmes. Note de contenu : Introduction
1.1 Soil Moisture
1.2 Production of soil moisture data
1.3 Soil moisture to build drought index
1.4 The innovative process set up for the VOD index
2. Creation of a standardized soil moisture index
2.1 Data
2.2 The soil moisture workflow
2.3 Optimization
3 Results of the SVODI process for SM
3.1 Australian use case
3.2 First results on Australia
3.3 Focus on extreme events in other regions of the world
3.4 World results
4. Correlation study, evaluate quantitatively the index
4.1 Methodology
4.2 Correlation study for the Australian use-case
4.3 World correlation study
ConclusionNuméro de notice : 26871 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Mémoire de projet pluridisciplinaire Organisme de stage : Department of Geodesy and Geoinformation (TU Wien) Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101700 Documents numériques
peut être téléchargé
Adaptation of the Standardized Vegetation Optical Depth Index for satellite-based soil moisture - pdf auteurAdobe Acrobat PDF Airborne LiDAR and high resolution multispectral data integration in Eucalyptus tree species mapping in an Australian farmscape / Niva Kiran Verma in Geocarto international, vol 37 n° 1 ([01/01/2022])
[article]
Titre : Airborne LiDAR and high resolution multispectral data integration in Eucalyptus tree species mapping in an Australian farmscape Type de document : Article/Communication Auteurs : Niva Kiran Verma, Auteur ; David Lamb, Auteur ; Priyakant Sinha, Auteur Année de publication : 2022 Article en page(s) : pp 70 - 90 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] Australie
[Termes IGN] carte de la végétation
[Termes IGN] dépérissement
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] Eucalyptus (genre)
[Termes IGN] image à haute résolution
[Termes IGN] image multibande
[Termes IGN] précision de la classification
[Termes IGN] segmentation d'image
[Termes IGN] semis de pointsRésumé : (auteur) Rapid decline and death of rural Eucalypts trees of all ages and species have been reported in the farmscapes of regional Australia due to various environmental and farming management related factors. The identification of existing farm tree species is important for long term management strategies to provide ecosystem stability in the region. This study explored the feasibility of structural attributes of LiDAR and spectral and spatial characteristics of high resolution remote sensing data to identify and map Eucalyptus tree species. An object based image segmentation and rule-based classification algorithm were developed to delineate tree boundaries and species classification. The integration of two datasets improved the classification accuracy (65%) against their separate classification (52% and 41%, respectively). The identification of tree species will help in getting first-hand information on existing farm trees, which may be used in assessing tree condition in time series related to management practices and complex dieback problem. Numéro de notice : A2022-046 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2019.1700555 Date de publication en ligne : 12/12/2019 En ligne : https://doi.org/10.1080/10106049.2019.1700555 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99412
in Geocarto international > vol 37 n° 1 [01/01/2022] . - pp 70 - 90[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 059-2022011 RAB Revue Centre de documentation En réserve L003 Disponible Mapping burned areas and land-uses in Kangaroo Island using an object-based image classification framework and Landsat 8 Imagery from Google Earth Engine / Jiyu Liu in Geomatics, Natural Hazards and Risk, vol 13 (2022)
[article]
Titre : Mapping burned areas and land-uses in Kangaroo Island using an object-based image classification framework and Landsat 8 Imagery from Google Earth Engine Type de document : Article/Communication Auteurs : Jiyu Liu, Auteur ; David Freudenberger, Auteur ; Lim Samsung, Auteur Année de publication : 2022 Article en page(s) : pp 1867 - 1897 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse d'image orientée objet
[Termes IGN] analyse spectrale
[Termes IGN] approche hiérarchique
[Termes IGN] Australie
[Termes IGN] carte thématique
[Termes IGN] écosystème forestier
[Termes IGN] Google Earth Engine
[Termes IGN] image infrarouge
[Termes IGN] image Landsat-8
[Termes IGN] incendie
[Termes IGN] Indien (océan)
[Termes IGN] segmentation d'image
[Termes IGN] utilisation du sol
[Termes IGN] zone sinistréeRésumé : (auteur) In Australia, fire has become part of the natural ecosystem. Severe fires have devastated Australia's unique forest ecosystems due to the global climate change. In this study, we integrated a multi-resolution segmentation method and a hierarchical classification framework based on expert-based knowledge to classify the burned areas and land-uses in Kangaroo Island, South Australia. Using an object-based image classification framework that combines colour and shape features from input layers, we demonstrated that the objects segmented from the multi-source data lead to a higher accuracy in classification with an overall accuracy of 90.2% and a kappa coefficient of 85.2%. On the other hand, the single source data from post-fire Landsat-8 imagery showed an overall accuracy of 87.4% which is also statistically acceptable. According to our experiment results, more than 30.44% of the study area was burned during the 2019–2020 ‘Black-Summer’ fire season in Australia. Among the burned areas, high severity accounted for 12.14%, moderate severity for 11.48%, while low severity was 6.82%. For unburned areas, farmland accounted for 45.52% of the study area, of which about one-third was affected by the disturbances other than fire. The remaining area consists of 19.42% unaffected forest, 3.48% building and bare land, and 1.14% water. The comparison analysis shows that our object-based image classification framework takes full advantage of the multi-source data and generates the edges of burned areas more clearly, which contributes to the improved fire management and control. Numéro de notice : A2022-873 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/19475705.2022.2098066 Date de publication en ligne : 02/08/2022 En ligne : https://doi.org/10.1080/19475705.2022.2098066 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102171
in Geomatics, Natural Hazards and Risk > vol 13 (2022) . - pp 1867 - 1897[article]Access to urban parks: Comparing spatial accessibility measures using three GIS-based approaches / Siqin Wang in Computers, Environment and Urban Systems, vol 90 (November 2021)
[article]
Titre : Access to urban parks: Comparing spatial accessibility measures using three GIS-based approaches Type de document : Article/Communication Auteurs : Siqin Wang, Auteur ; Mingshu Wang, Auteur ; Yan Liu, Auteur Année de publication : 2021 Article en page(s) : n° 101713 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] accessibilité
[Termes IGN] analyse en composantes principales
[Termes IGN] Australie
[Termes IGN] corrélation
[Termes IGN] distance
[Termes IGN] interaction spatiale
[Termes IGN] parc urbain
[Termes IGN] Pays-Bas
[Termes IGN] planification urbaine
[Termes IGN] transport urbainRésumé : (auteur) Urban parks are essential components of urban ecosystems, providing recreation and relaxation places to residents. Measuring the spatial accessibility to urban parks serves as an initial step in urban planning and developing urban development strategies to improve social and environmental justice. This study aims to evaluate measures of spatial accessibility to urban parks by comparing three geographic information systems (GIS)-based approaches, accounting for network complexity, transport modes, distance thresholds, and destination choices. Taking Ipswich City (Australia) and Enschede (the Netherlands) as two testbeds, we examine the spatial patterns of a total of 21 accessibility measures in the two cities and conduct a correlation and principal component analysis to unravel the interrelationship between these measures. The results suggest that among all measures under the three approaches, the selection of distance thresholds and transport modes matter more to accessibility measures than the destination choices. Furthermore, when distance threshold and transport mode are held constant, the network-based and entrance-based methods provide more realistic accessibility measures than other methods. We also discuss the generality of the entrance-based method we propose and suggest ways to choose the most appropriate accessibility measure for use in different contexts. Numéro de notice : A2021-698 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1016/j.compenvurbsys.2021.101713 Date de publication en ligne : 21/09/2021 En ligne : https://doi.org/10.1016/j.compenvurbsys.2021.101713 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98558
in Computers, Environment and Urban Systems > vol 90 (November 2021) . - n° 101713[article]Efficient measurement of large-scale decadal shoreline change with increased accuracy in tide-dominated coastal environments with Google Earth Engine / Yongjing Mao in ISPRS Journal of photogrammetry and remote sensing, Vol 181 (November 2021)PermalinkEvaluation of methods for connecting InSAR to a terrestrial reference frame in the Latrobe Valley, Australia / P.J. Johnston in Journal of geodesy, vol 95 n° 10 (October 2021)PermalinkA web GIS-based integration of 3D digital models with linked open data for cultural heritage exploration / Ikrom Nishanbaev in ISPRS International journal of geo-information, vol 10 n° 10 (October 2021)PermalinkA comparison of ALS and dense photogrammetric point clouds for individual tree detection in radiata pine plantations / Irfan A. Iqbal in Remote sensing, vol 13 n° 17 (September-1 2021)PermalinkUsing machine learning to map Western Australian landscapes for mineral exploration / Thomas Albrecht in ISPRS International journal of geo-information, vol 10 n° 7 (July 2021)PermalinkSelf-thinning tree mortality models that account for vertical stand structure, species mixing and climate / David I. Forrester in Forest ecology and management, Vol 487 ([01/05/2021])PermalinkDeep learning for wildfire progression monitoring using SAR and optical satellite image time series / Puzhao Zhang (2021)PermalinkPositional uncertainty of network RTK observations in a modern datum / T. Bernstein in Journal of geodetic science, vol 11 n° 1 (January 2021)PermalinkSocial media as passive geo-participation in transportation planning – how effective are topic modeling & sentiment analysis in comparison with citizen surveys? / Oliver Lock in Geo-spatial Information Science, vol 23 n° 4 (December 2020)PermalinkMapping the fantastic great Southern continent, 1760–1777: A study in enlightenment geography / Vanessa Collingridge in Cartographic journal (the), Vol 57 n° 4 (November 2020)Permalink