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Classification of glacial lakes using integrated approach of DFPS technique and gradient analysis using Sentinel 2A data / Prateek Verma in Geocarto international, vol 34 n° 10 ([15/07/2019])  

Public [article]  inGeocarto international > vol 34 n° 10 [15/07/2019] . - pp 1075 - 1088 Titre : Classification of glacial lakes using integrated approach of DFPS technique and gradient analysis using Sentinel 2A data Type de document : Article/Communication Auteurs : Prateek Verma, Auteur ; Sanjay Kumar Ghosh, Auteur Année de publication : 2019 Article en page(s) : pp 1075 - 1088 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes descripteurs IGN] changement climatique [Termes descripteurs IGN] glacier [Termes descripteurs IGN] Himalaya [Termes descripteurs IGN] image Sentinel-MSI [Termes descripteurs IGN] lac glaciaire [Termes descripteurs IGN] Normalized Difference Water Index [Termes descripteurs IGN] seuillage d'image [Termes descripteurs IGN] Uttarakhand (Inde ; état) Résumé : (auteur) It is important to identify and locate glacial lakes for assessing any potential hazard. This study presents a combination of semi-automatic method Double-Window Flexible Pace Search (DFPS) and edge detection technique to identify glacial lakes using Sentinel 2A satellite data. Initially, Normalized Difference Water Index (NDWI) has been used to identify water and non-water areas, while DFPS and Edge detection technique has been used to identify an optimum threshold value to distinguish between water and shadow areas. The optimal threshold from DFPS process is 0.21, while threshold value of gradient magnitude using edge detection process is 0.318. The number of glacial lakes identified using the above algorithm is in close agreement with previously published results on glacial lakes in Gangotri glacier using different techniques. Thus, a combination of DFPS and edge detection process has successfully segregated glacial lakes from other features present in Gangotri glacier. Numéro de notice : A2019-300 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2018.1469677 date de publication en ligne : 15/05/2018 En ligne : https://doi.org/10.1080/10106049.2018.1469677 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93220 [article]

Reconstruction of time-varying tidal flat topography using optical remote sensing imageries / Kuo-Hsin Tseng in ISPRS Journal of photogrammetry and remote sensing, vol 131 (September 2017)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 131 (September 2017) . - pp 92 - 103 Titre : Reconstruction of time-varying tidal flat topography using optical remote sensing imageries Type de document : Article/Communication Auteurs : Kuo-Hsin Tseng, Auteur ; Chung-Yen Kuo, Auteur ; Tang-Huang Lin, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 92 - 103 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes descripteurs IGN] données marégraphiques [Termes descripteurs IGN] estran [Termes descripteurs IGN] image Landsat-ETM+ [Termes descripteurs IGN] image Landsat-OLI [Termes descripteurs IGN] image Landsat-TM [Termes descripteurs IGN] marée océanique [Termes descripteurs IGN] modèle numérique de terrain [Termes descripteurs IGN] Normalized Difference Water Index [Termes descripteurs IGN] reconstruction automatique [Termes descripteurs IGN] Taïwan [Termes descripteurs IGN] variation temporelle Résumé : (Auteur) Tidal flats (TFs) occupy approximately 7% of the total coastal shelf areas worldwide. However, TFs are unavailable in most global digital elevation models (DEMs) due to water-impermeable nature of existing remote sensing approaches (e.g., radar used for WorldDEM™ and Shuttle Radar Topography Mission DEM and optical stereo-pairs used for ASTER Global Digital Elevation Map Version 2). However, this problem can be circumvented using remote sensing imageries to observe land exposure at different tidal heights during each revisit. This work exploits Landsat-4/-5/-7/-8 Thematic Mapper (TM)/Enhanced TM Plus/Operational Land Imager imageries to reconstruct topography of a TF, namely, Hsiang-Shan Wetland in Taiwan, to unveil its formation and temporal changes since the 1980s. We first classify water areas by applying modified normalized difference water index to each Landsat image and normalize chances of water exposure to create an inundation probability map. This map is then scaled by tidal amplitudes extracted from DTU10 tide model to convert the probabilities into actual elevations. After building DEM at intertidal zone, a water level-area curve is established, and accuracy of DEM is validated by sea level (SL) at the timing of each Landsat snapshot. A 22-year (1992–2013) dataset composed of 227 Landsat scenes are analyzed and compared with tide gauge data. Root-mean-square differences of SL reaches 48 cm with a correlation coefficient of 0.93, indicating that the present technique is useful for constructing accurate coastal DEMs, and that products can be utilized for estimating instant SL. This study shows the possibility of exploring evolution of intertidal zones using an archive of optical remote sensing imageries. The technique developed in the present study potentially helps in quantifying SL from the start of optical remote sensing era. Numéro de notice : A2017-538 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.07.008 En ligne : https://doi.org/10.1016/j.isprsjprs.2017.07.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86576 [article]

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Pan-sharpening of Landsat-8 images and its application in calculating vegetation greenness and canopy water contents / Khan Rubayet Rahaman in ISPRS International journal of geo-information, vol 6 n° 6 (June 2017)  

Public [article]  inISPRS International journal of geo-information > vol 6 n° 6 (June 2017) . - pp Titre : Pan-sharpening of Landsat-8 images and its application in calculating vegetation greenness and canopy water contents Type de document : Article/Communication Auteurs : Khan Rubayet Rahaman, Auteur ; Quazi K. Hassan, Auteur ; M. Razu Ahmed, Auteur Année de publication : 2017 Article en page(s) : pp Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes descripteurs IGN] Calgary [Termes descripteurs IGN] Enhanced vegetation index [Termes descripteurs IGN] fusion d'images [Termes descripteurs IGN] image Landsat-8 [Termes descripteurs IGN] image multibande [Termes descripteurs IGN] image panchromatique [Termes descripteurs IGN] Normalized Difference Vegetation Index [Termes descripteurs IGN] Normalized Difference Water Index [Termes descripteurs IGN] pansharpening (fusion d'images) Résumé : (Auteur) Pan-sharpening is the process of fusing higher spatial resolution panchromatic (PAN) with lower spatial resolution multispectral (MS) imagery to create higher spatial resolution MS images. Here, our overall objective was to pan-sharpen Landsat-8 images and calculate vegetation greenness (i.e., normalized difference vegetation index (NDVI)), canopy structure (i.e., enhanced vegetation index (EVI)), and canopy water content (i.e., normalized difference water index (NDWI))-related variables. Our proposed methods consisted of: (i) evaluating the relationships between PAN band (0.503–0.676 µm) with a spatial resolution of 15 m and individual MS bands of Landsat-8 from blue (i.e., acquiring in the range 0.452–0.512 µm), green (i.e., 0.533–0.590 µm), red (i.e., 0.636–0.673 µm), near infrared (NIR: 0.851–0.879 µm), shortwave infrared-I (SWIR-I: 1.566–1.651 µm), and SWIR-II (2.107–2.294 µm) bands with a spatial resolution of 30 m; (ii) determining the suitable individual MS bands to be enhanced into the spatial resolution of the PAN band; and (iii) calculating several vegetation greenness and canopy moisture indices (i.e., NDVI, EVI, NDWI-I, and NDWI-II) at 15 m spatial resolution and subsequent validation using their equivalent-values at a spatial resolution of 30 m. Our analysis revealed that strong linear relationships existed between the PAN and most of the MS individual bands of interest except NIR. For example, r2 values were 0.86–0.89 for blue band; 0.89–0.95 for green band; 0.84–0.96 for red band; 0.71–0.79 for SWIR-I band; and 0.71–0.83 for SWIR-II band. As a result, we performed smoothing filter-based intensity modulation method of pan-sharpening to enhance the spatial resolution of 30 m to 15 m. In calculating the vegetation indices, we used the enhanced MS images and resampled the NIR to 15 m. Finally, we evaluated these indices with their equivalents at 30 m spatial resolution and observed strong relationships (i.e., r2 values in the range 0.98–0.99 for NDVI, 0.95–0.98 for EVI, 0.98–1.00 for NDWI). Numéro de notice : A2017-811 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi6060168 En ligne : https://doi.org/10.3390/ijgi6060168 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89251 [article]

Object-based water body extraction model using Sentinel-2 satellite imagery / Gordana Kaplan in European journal of remote sensing, vol 50 n° 1 (2017)  

Public [article]  inEuropean journal of remote sensing > vol 50 n° 1 (2017) . - pp 143 - 150 Titre : Object-based water body extraction model using Sentinel-2 satellite imagery Type de document : Article/Communication Auteurs : Gordana Kaplan, Auteur ; Ugur Avdan, Auteur Année de publication : 2017 Article en page(s) : pp 143 - 150 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes descripteurs IGN] analyse d'image orientée objet [Termes descripteurs IGN] extraction automatique [Termes descripteurs IGN] image multibande [Termes descripteurs IGN] image Sentinel-MSI [Termes descripteurs IGN] lac [Termes descripteurs IGN] Macédoine [Termes descripteurs IGN] Normalized Difference Water Index [Termes descripteurs IGN] segmentation d'image Résumé : (auteur) Water body extraction is an important part of water resource management and has been the topic of a number of research works related to remote sensing for over two decades. Extracting water bodies from satellite images with a pixel-based method or indexes cannot eliminate other objects that have a low albedo, such as shadows and built-up areas. Since their spectral differences cannot be separated, in this paper a method that combines a pixel-based index and object-based method has been used on a Sentinel-2 satellite image with a resolution of 10 m. The method uses image segmentation on a multispectral image containing 13 bands. It also uses indexes used for extracting water bodies, such as the Normalized Difference Water Index (NDWI). Two study areas with different characteristics have been chosen, one mountainous and one urban region, both of them located in Macedonia. Using object-based techniques and pixel-based indexes, such as NDWI, the results from the NDWI have been improved by a kappa value of more than 0.5. Numéro de notice : A2017-719 Thématique : IMAGERIE Nature : Article DOI : 10.1080/22797254.2017.1297540 En ligne : https://doi.org/10.1080/22797254.2017.1297540 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88375 [article]

Classification of biodiversity in Doi Inthanon national parc / H. Draux (2007)

Public Titre : Classification of biodiversity in Doi Inthanon national parc Type de document : Mémoire Auteurs : H. Draux, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2007 Importance : 37 p. Format : 21 x 30 cm Note générale : Report of multi-field projet, cycle des ingénieurs diplômés de l'ENSG 2ème année (IT2) Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes descripteurs IGN] analyse spatiale [Termes descripteurs IGN] biodiversité [Termes descripteurs IGN] carte thématique [Termes descripteurs IGN] classification automatique [Termes descripteurs IGN] correction d'image [Termes descripteurs IGN] image Landsat [Termes descripteurs IGN] image SPOT 5 [Termes descripteurs IGN] Normalized Difference Vegetation Index [Termes descripteurs IGN] Normalized Difference Water Index [Termes descripteurs IGN] parc naturel national [Termes descripteurs IGN] Thaïlande Index. décimale : PROJET Rapports de projet - stage des ingénieurs de 2e année Résumé : (Auteur) Ce document est le résultat d'un stage de trois mois effectué de Juin à Août 2007 au sein de la GISDTA à Bangkok (Thaïlande), dans le cadre de la seconde année du cycle d'Ingénieur de l'ENSG. Son objectif était de mieux comprendre la biodiversité existante dans le parc national "Doi Inthanon", en réalisant une classification de la zone à partir d'images satellites issues des capteurs des satellites de SPOT-5 et Landsat 5, ainsi que d'écrire un modèle capable de décrire les composantes des différentes classes. Note de contenu : Introduction 1. Inventory of the data 1. Satellite images 2. Data collected into the field 3. Thai forests 3.1. Characteristics 3.2. Distribution 2. Data processing 1. SPOT-5 2. LANDSAT 5 2.1. Geo-referencing 2.2. Model maker 3. Classifications 3.1. Manual classification 3.1.a. Segmentation 3.1.b. Choices 3.2. Automatic classification 3.2.a. Result 3.2.b. Comparison between the visual classification and the model 3. Interpretations 1. Indexes 1.1. Normalized Difference Vegetation Index (NDVI) 1.2. Temperature 1.3. Water Index 1.4. Model 2. Biodiversity 3. Propositions to improve the model Conclusion Numéro de notice : 19125 Thématique : BIODIVERSITE/IMAGERIE Nature : Mémoire de projet pluridisciplinaire Organisme de stage : Geo-Informatics and Space Technology Development Agency (Thailande) Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=51064

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Estimation of leaf water status to monitor the risk of forest fires by using remotely sensed data / M. Maki in Remote sensing of environment, vol 90 n° 4 (30/04/2004)

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