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Efficiently computing the drainage network on massive terrains using external memory flooding process / Thiago L. Gomes in Geoinformatica, vol 19 n° 4 (October - December 2015)
[article]
Titre : Efficiently computing the drainage network on massive terrains using external memory flooding process Type de document : Article/Communication Auteurs : Thiago L. Gomes, Auteur ; Salles V. G. Magalhães, Auteur ; Marcus V. A. Andrade, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 671 - 692 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique
[Termes IGN] écoulement des eaux
[Termes IGN] hydrologie
[Termes IGN] modèle numérique de terrain
[Termes IGN] réseau d'irrigation
[Termes IGN] système d'information géographiqueRésumé : (auteur) We present EMFlow, a very efficient algorithm and its implementation, to compute the drainage network (i.e. the flow direction and flow accumulation) on huge terrains stored in external memory. Its utility lies in processing the large volume of high resolution terrestrial data newly available, which internal memory algorithms cannot handle efficiently. The flow direction is computed using an adaptation of our previous method RWFlood that uses a flooding process to quickly remove internal depressions or basins. Flooding, proceeding inward from the outside of the terrain, works oppositely to the common method of computing downhill flow from the peaks. To reduce the number of I/O operations, EMFlow adopts a new strategy to subdivide the terrain into islands that are processed separately. The terrain cells are grouped into blocks that are stored in a special data structure managed as a cache memory. EMFlow’s execution time was compared against the two most recent and most efficient published methods: TerraFlow and r.watershed.seg. It was, on average, 25 and 110 times faster than TerraFlow and r.watershed.seg respectively. Also, EMFlow could process larger datasets. Processing a 50000 × 50000 terrain on a machine with 2GB of internal memory took about 4500 seconds, compared to 87000 seconds for TerraFlow while r.watershed.seg failed on terrains larger than 15000 ×15000. On very small, say1000 ×1000 terrains, EMFlow takes under a second, compared to 6 and 20 seconds in r.watershed.seg and TerraFlow respectively. So EMFlow could be a component of a future interactive system where a user could modify terrain and immediately see the new hydrography. Numéro de notice : A2015--034 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-015-0225-y En ligne : https://doi.org/10.1007/s10707-015-0225-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81120
in Geoinformatica > vol 19 n° 4 (October - December 2015) . - pp 671 - 692[article]Land cover changes assessment using object-based image analysis in the Binah River watershed (Togo and Benin) / Hèou Maléki Badjana in Earth and space science, vol 2 n° 10 (October 2015)
[article]
Titre : Land cover changes assessment using object-based image analysis in the Binah River watershed (Togo and Benin) Type de document : Article/Communication Auteurs : Hèou Maléki Badjana, Auteur ; Jörg Helmschrot, Auteur ; Peter Selsam, Auteur ; Kperkouma Wala, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 403 - 416 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse d'image orientée objet
[Termes IGN] analyse diachronique
[Termes IGN] bassin hydrographique
[Termes IGN] Bénin
[Termes IGN] changement d'occupation du sol
[Termes IGN] déboisement
[Termes IGN] détection de changement
[Termes IGN] image Landsat-MSS
[Termes IGN] image Landsat-OLI
[Termes IGN] image Landsat-TM
[Termes IGN] occupation du sol
[Termes IGN] savane
[Termes IGN] TogoRésumé : (auteur) In this study, land cover changes between 1972 and 2013 were investigated in the Binah River watershed (North of Togo and Benin) using remote sensing and geographic information system technologies. Multitemporal satellite images—Landsat MSS (1972), TM (1987), and OLI-TIRS (2013)—were processed using object-based image analysis and post–classification comparison methods including landscape metrics and changes trajectories analysis. Land cover maps referring to five main land cover classes, namely, agricultural land, forest land, savannah, settlements, and water bodies, were produced for each acquisition date. The overall accuracies were 76.64% (1972), 83.52% (1987), and 88.84% (2013) with respective Kappa statistics of 0.69, 0.78, and 0.86. The assessment of the spatiotemporal pattern of land cover changes indicates that savannah, the main vegetation type, has undergone the most dominant change, decreasing from 67% of the basin area in 1972 to 56% in 1987 and 33% in 2013. At the same time, agricultural land has significantly increased from 15% in 1972 to 24% in 1987 and 43% in 2013, while some proportions of agricultural land were converted to savannah relating to fallow agriculture. In total, more than 55% of the landscape experienced changes between 1972 and 2013. These changes are primarily due to human activities and population growth. In addition, agricultural activities significantly contributed to the increase in the number of patches, degree of division, and splitting index of forest and savannah vegetations and the decrease in their effective mesh sizes. These results indicate further fragmentation of forest and savannah vegetations between 1972 and 2013. Further research is needed to quantitatively evaluate the influences of individual factors of human activities and to separate these from the impacts of climate change-driven disturbances. Numéro de notice : A2015--042 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : doi.org/10.1002/2014EA000083 En ligne : http://dx.doi.org/10.1002/2014EA000083 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81804
in Earth and space science > vol 2 n° 10 (October 2015) . - pp 403 - 416[article]Quantitative assessment of the sensitivity to desertification in the Bradano River basin (Basilicata, southern Italy) / Filomena Canora in Journal of maps, vol 11 n° 5 ([01/10/2015])
[article]
Titre : Quantitative assessment of the sensitivity to desertification in the Bradano River basin (Basilicata, southern Italy) Type de document : Article/Communication Auteurs : Filomena Canora, Auteur ; Annachiara d'Angella, Auteur ; Antonello Aiello, Auteur Année de publication : 2015 Article en page(s) : pp 745 -759 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse de sensibilité
[Termes IGN] ArcGIS
[Termes IGN] bassin hydrographique
[Termes IGN] climat méditerranéen
[Termes IGN] désertification
[Termes IGN] évaluation
[Termes IGN] littoral méditerranéenRésumé : (auteur) Desertification is a complex environmental phenomenon that affects many regions worldwide, including the Mediterranean area. Its effects, primarily resulting from climate variations and also influenced by human-induced changes, impact upon potential regional progress due to significant economic losses, social problems and ecological damage. The aim of this study was the identification of sensitive areas to desertification at watershed scale, in the Bradano River basin (Basilicata, southern Italy). The analysis was carried out by means of the model developed within the European project MEDALUS (MEditerranean Desertification And Land USe), which identifies prone areas to desertification through the Environmentally Sensitive Areas (ESAs) index. The model parameters were implemented and processed using a GIS-based approach to evaluate climate, soil, vegetation and management system quality factors, which represent the input for the ESAs assessment. The results indicate that 35% of the study area is highly sensitive to desertification, 49% of the study area has moderate sensitivity to desertification, 12% has low sensitivity and only 4% is non-sensitive to desertification. Numéro de notice : A2015-546 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE Nature : Article DOI : 10.1080/17445647.2014.980857 En ligne : https://doi.org/10.1080/17445647.2014.980857 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77520
in Journal of maps > vol 11 n° 5 [01/10/2015] . - pp 745 -759[article]GIS based drainage morphometry and its influence on hydrology in parts of Western Ghats region, Maharashtra, India / Dipak R. Samal in Geocarto international, vol 30 n° 7 - 8 (August - September 2015)
[article]
Titre : GIS based drainage morphometry and its influence on hydrology in parts of Western Ghats region, Maharashtra, India Type de document : Article/Communication Auteurs : Dipak R. Samal, Auteur ; Shirish S. Gedam, Auteur ; R. Nagarajan, Auteur Année de publication : 2015 Article en page(s) : pp 755 - 778 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] analyse multicritère
[Termes IGN] base de données thématiques
[Termes IGN] bassin hydrographique
[Termes IGN] carte topographique
[Termes IGN] corrélation
[Termes IGN] géomorphométrie
[Termes IGN] Ghats occidentaux
[Termes IGN] hydrographie de surface
[Termes IGN] Inde
[Termes IGN] intégration de données
[Termes IGN] Maharashtra (Inde ; état)
[Termes IGN] matrice
[Termes IGN] MNS ASTER
[Termes IGN] système d'information géographiqueRésumé : (Auteur) Various drainage morphometric parameters in the Upper Bhima river basin and its influence on hydrological processes (e.g. runoff, peak flow, time to peak, infiltration, overland flow, etc.) were discussed using geographical information system (GIS) and remote sensing techniques. Survey of India topographical maps and ASTER digital elevation model was incorporated for thematic database generation and morphometric parameter evaluation in GIS environment. The whole study basin was divided into 8 sub-basins so that the spatial variation of morphological parameters and its influence on hydrology could be analyzed. The interrelationship between morphometric variables were computed (p Numéro de notice : A2015-501 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2014.978903 Date de publication en ligne : 15/06/2015 En ligne : http://www.tandfonline.com/doi/full/10.1080/10106049.2014.978903 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77417
in Geocarto international > vol 30 n° 7 - 8 (August - September 2015) . - pp 755 - 778[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-2015041 RAB Revue Centre de documentation En réserve L003 Disponible Bathymetry of lake Constance – a high-resolution survey in a large, deep lake / Martin Wessels in ZFV, Zeitschrift für Geodäsie, Geoinformation und Landmanagement, Vol 140 n° 4 (Juli - August 2015)
[article]
Titre : Bathymetry of lake Constance – a high-resolution survey in a large, deep lake Type de document : Article/Communication Auteurs : Martin Wessels, Auteur ; Flavio Anselmetti, Auteur ; Roberto Artuso, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 203 - 210 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bathymétrie
[Termes IGN] lac
[Termes IGN] lidar bathymétrique
[Termes IGN] modèle numérique bathymétrique
[Termes IGN] sondeur multifaisceaux
[Termes IGN] télémétrie laser aéroporté
[Termes IGN] traitement combinéRésumé : (Auteur) Within the project “Tiefenschärfe – hochauflösende Vermessung Bodensee” a high-resolution seamless terrain model is created using airborne topobathymetric laserscanning and multibeam echosounder (MBES) techniques. The project visualizes the enormous wealth of features of underwater landscapes of lakes. The combination of hydroacoustic (multibeam echosounder) and laser-optic (topobathymetric laserscanning) methods was used for the first time in a freshwater body of this size. Opportunities, limitations and restrictions of these high-resolution methods are presented. Numéro de notice : A2015-746 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78741
in ZFV, Zeitschrift für Geodäsie, Geoinformation und Landmanagement > Vol 140 n° 4 (Juli - August 2015) . - pp 203 - 210[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 199-2015041 RSREV Revue Centre de documentation Revues en salle Disponible Vulnérabilité et adaptation au changement climatique : L'apport des Géosciences / Gonéri Le Cozannet in Géosciences, Hors série sans n° (juillet 2015)PermalinkObjets géographiques et relativité d’échelle / Maxime Forriez in Revue internationale de géomatique, vol 25 n° 2 (juin - août 2015)PermalinkDossier inondations : quoi de neuf ? / Françoise de Blomac in DécryptaGéo le mag, n° 167 (mai 2015)PermalinkEvaluation of Lidar-derived DEMs through terrain analysis and field / Cody P. Gillin in Photogrammetric Engineering & Remote Sensing, PERS, vol 81 n° 5 (May 2015)PermalinkInondations : Mobilisation générale / Françoise de Blomac in DécryptaGéo le mag, n° 167 (mai 2015)PermalinkPredicting floods with GPS / Paul Grad in Position, n° 76 (April - May 2015)PermalinkUn système décisionnel pour l’analyse de la qualité des eaux de rivières / Sandro Bimonte in Ingénierie des systèmes d'information, ISI : Revue des sciences et technologies de l'information, RSTI, vol 20 n° 3 (mai - juin 2015)PermalinkA geographic approach for combining social media and authoritative data towards identifying useful information for disaster management / João Porto de Albuquerque in International journal of geographical information science IJGIS, vol 29 n° 4 (April 2015)PermalinkAppariement hiérarchique de réseaux hydrographiques imparfaits / Benoit Costes in Revue internationale de géomatique, vol 25 n° 1 (mars - mai 2015)PermalinkComparison of basin morphometry derived from topographic maps, ASTER and SRTM DEMs: an example from Kerala, India / Jobin Thomas in Geocarto international, vol 30 n° 3 - 4 (March - April 2015)Permalink