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Comparative analysis of the accuracy of surface soil moisture estimation from the C- and L-bands / Mohammad El Hajj in International journal of applied Earth observation and geoinformation, vol 82 (October 2019)
[article]
Titre : Comparative analysis of the accuracy of surface soil moisture estimation from the C- and L-bands Type de document : Article/Communication Auteurs : Mohammad El Hajj, Auteur ; Nicolas Baghdadi, Auteur ; Mehrez Zribi, Auteur Année de publication : 2019 Article en page(s) : 13 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] analyse comparative
[Termes IGN] bande C
[Termes IGN] bande L
[Termes IGN] humidité du sol
[Termes IGN] image ALOS-PALSAR
[Termes IGN] image radar moirée
[Termes IGN] image Sentinel-MSI
[Termes IGN] image Sentinel-SAR
[Termes IGN] Normalized Difference Water Index
[Termes IGN] réseau neuronal artificiel
[Termes IGN] surface cultivéeRésumé : (auteur) Surface soil moisture (SSM) estimation is of great importance in several areas, such as hydrology, agriculture and risk assessment. C-band SAR (synthetic aperture radar) data have been widely used to estimate SSM, whereas few studies have been performed using L-band SAR due to the low availability of L-band SAR data. In this context, the objective of the present paper is to compare the SSM estimation potentials of the C- (Sentinel-1) and L-bands (PALSAR) for wheat and grassland plots. The inversion approach developed in this study uses neural networks to invert the SAR signal and estimate the SSM. For each radar frequency, the developed neural networks were trained using the following as an input vector: SAR incidence angle, SAR polarization (VV for the C-band and HH for the L-band), and NDVI from optical images. Artificial Neural networks (ANNs) were developed and validated using synthetic and real databases. The results showed that the L-band provided slightly less accurate SSM estimates than the C-band. Moreover, the results showed that the accuracies of the SSM estimates for both frequencies strongly depended on the soil roughness (Hrms) and SSM values. From the synthetic database at SSM values less than 25 vol.%, the ANNs underestimated the SSM for Hrms values less than 1.5 cm and overestimated the SSM for Hrms values greater than 1.5 cm. In addition, the ANNs underestimated the SSM value regardless of the Hrms value when the SSM value was greater than 25 vol.%. An RMSE analysis of the SSM estimates showed that the highest RMSE values were observed for the L-band regardless of the SSM value, and high RMSE values were observed for the C-band only in very wet soil conditions (SSM>25 vol.%). From the real database at NDVI values less than 0.7, the RMSE (root mean square error) of the SSM estimates was 4.6 vol.% for the C-band and 5.3 vol.% for the L-band. Most importantly, the L-band enabled the estimation of the SSM under a well-developed vegetation cover (NDVI > 0.7) with an RMSE of 6.7 vol.%, whereas the C-band SAR signal became completely attenuated for some crops when the NDVI value was greater than 0.7, and thus the estimation of SSM was impossible using the C-band. Numéro de notice : A2019-473 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jag.2019.05.021 Date de publication en ligne : 29/06/2019 En ligne : https://doi.org/10.1016/j.jag.2019.05.021 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93634
in International journal of applied Earth observation and geoinformation > vol 82 (October 2019) . - 13 p.[article]Using a U-net convolutional neural network to map woody vegetation extent from high resolution satellite imagery across Queensland, Australia / Neil Flood in International journal of applied Earth observation and geoinformation, vol 82 (October 2019)
[article]
Titre : Using a U-net convolutional neural network to map woody vegetation extent from high resolution satellite imagery across Queensland, Australia Type de document : Article/Communication Auteurs : Neil Flood, Auteur ; Fiona Watson, Auteur ; Lisa Collett, Auteur Année de publication : 2019 Article en page(s) : 15 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] apprentissage profond
[Termes IGN] arbre (flore)
[Termes IGN] arbuste
[Termes IGN] bois sur pied
[Termes IGN] carte de la végétation
[Termes IGN] données d'entrainement (apprentissage automatique)
[Termes IGN] image à haute résolution
[Termes IGN] image satellite
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] mosaïque d'images
[Termes IGN] Queensland (Australie)
[Termes IGN] réseau neuronal convolutif
[Termes IGN] texture d'imageRésumé : (auteur) Convolutional neural networks offer a new approach to classifying high resolution imagery. We use the U-net neural network architecture to map the presence or absence of trees and large shrubs across the Australian state of Queensland. From a state-wide mosaic of 1 m resolution 3-band Earth-i imagery, a selection of 827 squares (1 km2) are manually labeled for the presence of trees or large shrubs, and these are used to train the neural network. The training is intended to capture the textures which are primary visual cues of such vegetation. The trained neural network has an accuracy on independent data of around 90%. The resulting map over the whole of Queensland (1.73 million km2) is intended to be manually checked, and edited where necessary, to provide a high quality map of woody vegetation extent to serve a range of government policy objectives. Numéro de notice : A2019-474 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jag.2019.101897 Date de publication en ligne : 28/06/2019 En ligne : https://doi.org/10.1016/j.jag.2019.101897 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93635
in International journal of applied Earth observation and geoinformation > vol 82 (October 2019) . - 15 p.[article]Multitemporal Landsat-MODIS fusion for cropland drought monitoring in El Salvador / Nguyen-Thanh Son in Geocarto international, vol 34 n° 12 ([15/09/2019])
[article]
Titre : Multitemporal Landsat-MODIS fusion for cropland drought monitoring in El Salvador Type de document : Article/Communication Auteurs : Nguyen-Thanh Son, Auteur ; Chi-Farn Chen, Auteur ; Cheng-Ru Chen, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 1363 - 1383 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse spatio-temporelle
[Termes IGN] bande infrarouge
[Termes IGN] classification par forêts d'arbres décisionnels
[Termes IGN] climat tropical
[Termes IGN] coefficient de corrélation
[Termes IGN] fusion de données
[Termes IGN] image Aqua-MODIS
[Termes IGN] image Landsat
[Termes IGN] image Terra-MODIS
[Termes IGN] saison
[Termes IGN] Salvador
[Termes IGN] sécheresse
[Termes IGN] surface cultivée
[Termes IGN] température au solRésumé : (Auteur) This study aims to develop an approach to characterize cropland drought conditions in El Salvador, Central America. The data were processed for 2016–2017 through three main steps: (1) reconstructing MODIS land-surface temperature (LST), (2) Landsat-MODIS data fusion and (3) drought delineation using the temperature vegetation dryness index (TVDI). The results of LST reconstruction using the random forests (RF) indicated the median RMSE value of 0.5 °C. The fusion results achieved from the STARFM compared with the reference Landsat data revealed close agreement with the correlation coefficient (r) values higher than 0.84. The TVDI results verified with that from the reference Landsat data indicated r values of 0.85 and 0.75 for 2016 and 2017, respectively. The larger very dry area was observed for the 2016 primera season due to prolonged droughts. Approximately 11.5% and 10.7% of croplands were, respectively, associated with very dry moisture condition in the 2016 and 2017 primera seasons. Numéro de notice : A2019-466 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2018.1489421 Date de publication en ligne : 07/09/2018 En ligne : https://doi.org/10.1080/10106049.2018.1489421 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93619
in Geocarto international > vol 34 n° 12 [15/09/2019] . - pp 1363 - 1383[article]Change detection work-flow for mapping changes from arable lands to permanent grasslands with advanced boosting methods / Jiří Šandera in Geodetski vestnik, vol 63 n° 3 (September - November 2019)
[article]
Titre : Change detection work-flow for mapping changes from arable lands to permanent grasslands with advanced boosting methods Type de document : Article/Communication Auteurs : Jiří Šandera, Auteur ; Přemysl Štych, Auteur Année de publication : 2019 Article en page(s) : pp 379 - 394 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse diachronique
[Termes IGN] apprentissage automatique
[Termes IGN] boosting adapté
[Termes IGN] carte d'occupation du sol
[Termes IGN] chaîne de traitement
[Termes IGN] changement d'occupation du sol
[Termes IGN] détection de changement
[Termes IGN] image Landsat
[Termes IGN] prairie
[Termes IGN] terre arableRésumé : (Auteur) The necessity of mapping changes in land cover categories based on satellite imageries is a challenging task especially in terms of arable land and grasslands. The phenological phases of arable lands change quickly while grasslands is more stable. It might be hard to capture these changes regarding the spectral overlap between crops in full growth and grass itself. We have introduced a relatively simple processing workflow with good efficiency and accuracy. Our proposed method utilises the combination of a Multivariate Alteration Change Detection Algorithm and an existing boosting method, such as the AdaBoost algorithm with different weak learners and the most recent one – Extreme Gradient Boosting that is actually a relatively new approach in remote sensing. According to the results, the highest overall accuracy is 89.51 %. The proposed process workflow was tested on Landsat data with 30 m spatial resolution, using open-source software: R and GRASS GIS, Orfeo Toolbox library. Numéro de notice : A2019-501 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.15292/geodetski-vestnik.2019.03.379-394 En ligne : http://dx.doi.org/10.15292/geodetski-vestnik.2019.03.379-394 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93783
in Geodetski vestnik > vol 63 n° 3 (September - November 2019) . - pp 379 - 394[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 139-2019031 RAB Revue Centre de documentation En réserve L003 Disponible Cultures of Enthusiasm: An Ethnographic Study of Amateur Map-Maker Communities / Mike Duggan in Cartographica, vol 54 n° 3 (Fall 2019)
[article]
Titre : Cultures of Enthusiasm: An Ethnographic Study of Amateur Map-Maker Communities Type de document : Article/Communication Auteurs : Mike Duggan, Auteur Année de publication : 2019 Article en page(s) : pp 217 - 229 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique
[Termes IGN] carte thématique
[Termes IGN] données localisées des bénévoles
[Termes IGN] épistémologie
[Termes IGN] ethnographie
[Termes IGN] OpenStreetMap
[Termes IGN] production cartographiqueRésumé : (auteur) Further attention should be paid to contextualizing the spaces and practices of amateur map-making. Doing so will provide further insight into the ways that maps, mapping epistemologies, and mapper identities emerge in the practices of everyday life. In order to deconstruct the map, and ultimately the power of maps, it is necessary to investigate maps from the bottom up as well as the top down. The motivations of amateur cartographers, the contexts in which map-making takes place, and the technological processes involved are all important factors to consider when examining how and why maps are produced. Empirical ethnographic evidence from a study of OpenStreetMap and humanitarian “mapping parties” is presented here to demonstrate how the often overlooked cultures of amateur map-making offer novel perspectives on who contemporary map-makers are and what motivates them to map. It is shown that amateur map-making is a broad category that includes close-knit hobby communities and more diverse groups of enthusiastic volunteers. As cartography continues to open up and become more accessible through a range of digital mapping technologies, studying these shifts will be important for understanding how and why the role of the map in contemporary life is changing. Numéro de notice : A2019-542 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3138/cart.54.3.2018-0002 Date de publication en ligne : 18/09/2017 En ligne : https://doi.org/10.3138/cart.54.3.2018-0002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94182
in Cartographica > vol 54 n° 3 (Fall 2019) . - pp 217 - 229[article]Réservation
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