Fine-grained landuse characterization using ground-based pictures: a deep learning solution based on globally available data   总被引：1，自引：0，他引：1  

Shivangi Srivastava  John E. Vargas Muñoz  Sylvain Lobry  Devis Tuia 《International journal of geographical information science》2020,34(6):1117-1136

ABSTRACT

We study the problem of landuse characterization at the urban-object level using deep learning algorithms. Traditionally, this task is performed by surveys or manual photo interpretation, which are expensive and difficult to update regularly. We seek to characterize usages at the single object level and to differentiate classes such as educational institutes, hospitals and religious places by visual cues contained in side-view pictures from Google Street View (GSV). These pictures provide geo-referenced information not only about the material composition of the objects but also about their actual usage, which otherwise is difficult to capture using other classical sources of data such as aerial imagery. Since the GSV database is regularly updated, this allows to consequently update the landuse maps, at lower costs than those of authoritative surveys. Because every urban-object is imaged from a number of viewpoints with street-level pictures, we propose a deep-learning based architecture that accepts arbitrary number of GSV pictures to predict the fine-grained landuse classes at the object level. These classes are taken from OpenStreetMap. A quantitative evaluation of the area of Île-de-France, France shows that our model outperforms other deep learning-based methods, making it a suitable alternative to manual landuse characterization.  相似文献   

Impact of the unpredictable changes in agricultural groundwater use on long-term sustainable exploitation: the case study of Bouhefna-Haffouz aquifer system,central Tunisia     

Jerbi  Hamza  Sebai  Amal  Massuel  Sylvain  Riaux  Jeanne  Leduc  Christian  Tarhouni  Jamila 《Hydrogeology Journal》2023,31(5):1181-1196

Long-term exploitation schemes in many regions are often based solely on hydrodynamic factors, while the agricultural use of groundwater undergoes significant changes over time. The Bouhefna-Haffouz aquifer system in central Tunisia is one of those cases where an aquifer exploitation scheme was well designed hydrodynamically to address the political needs at the time. Fifty years later, a numerical groundwater model has been conducted to assess the sustainability of the scheme. Results show that the scheme aimed to lower the groundwater level to reduce overflow to Merguellil Wadi and maintain it at a level that benefits agricultural profitability. This caused loss of the Merguellil baseflow, forcing farmers to switch from traditional irrigation canals to deep wells and motor pumps, thereby disrupting the hydrological budget even further. The numerical model indicates that the flow to the wadi reached zero in 1978, the average flow by vertical leakage decreased from 8 hm³ in 1970 to 2 hm³ in 2020, and the horizontal percolation between the regional aquifer units increased from 1 hm³ in 1970 to 6 hm³ in 2020. Although the groundwater exploitation scheme was not previously considered a factor in local hydrological changes, the results of this study demonstrate the significant impact of societal behavior following the scheme’s implementation on the hydrological budget of Merguellil Wadi.

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How do Canadian media report climate change impacts on health? A newspaper review     

King  Nia  Bishop-Williams  Katherine E.  Beauchamp  Sabrina  Ford  James D.  Berrang-Ford  Lea  Cunsolo  Ashlee  Team  IHACC Research  Harper  Sherilee L. 《Climatic change》2019,152(3-4):581-596

Climatic Change - Research on climate change media coverage is growing. Few studies, however, have investigated how the media portrays climate change impacts on human health. This review,...  相似文献   

Albedo control of seasonal South Polar cap recession on Mars     

Frédéric Schmidt  Sylvain Douté  Bernard Schmitt  Mathieu Vincendon  Jean-Pierre Bibring  Yves Langevin  The OMEGA Team 《Icarus》2009,200(2):374-394

Over the last few decades, General Circulation Models (GCM) have been used to simulate the current martian climate. The calibration of these GCMs with the current seasonal cycle is a crucial step in understanding the climate history of Mars. One of the main climatic signals currently used to validate GCMs is the annual atmospheric pressure cycle. It is difficult to use changes in seasonal deposits on the surface of Mars to calibrate the GCMs given the spectral ambiguities between CO₂ and H₂O ice in the visible range. With the OMEGA imaging spectrometer covering the near infra-red range, it is now possible to monitor both types of ice at a spatial resolution of about 1 km. At global scale, we determine the change with time of the Seasonal South Polar Cap (SSPC) crocus line, defining the edge of CO₂ deposits. This crocus line is not symmetric around the geographic South Pole. At local scale, we introduce the snowdrop distance, describing the local structure of the SSPC edge. Crocus line and snowdrop distance changes can now be used to calibrate GCMs. The albedo of the seasonal deposits is usually assumed to be a uniform and constant parameter of the GCMs. In this study, albedo is found to be the main parameter controlling the SSPC recession at both global and local scale. Using a defrost mass balance model (referred to as D-frost) that incorporates the effect of shadowing induced by topography, we show that the global SSPC asymmetry in the crocus line is controlled by albedo variations. At local scale, we show that the snowdrop distance is correlated with the albedo variability. Further GCM improvements should take into account these two results. We propose several possibilities for the origin of the asymmetric albedo control. The next step will be to identify and model the physical processes that create the albedo differences.  相似文献   

Analytical and numerical analyses of the load‐bearing capacity of retaining walls laterally supported at both ends     

Sylvain Plumey  Aurelio Muttoni  Laurent Vulliet  Vincent Labiouse 《国际地质力学数值与分析法杂志》2011,35(9):1019-1033

This paper investigates the load‐bearing capacity of a perfectly smooth retaining wall laterally supported at both ends assuming that the wall fails by the development of three plastic hinges. The study considers the case of a cohesionless elastic–perfectly plastic backfill with a Mohr–Coulomb yield criterion and an associative flow rule in drained conditions. A kinematically admissible soil–structure failure mechanism is proposed and compared with the conventional solutions and with results from a numerical finite element modelling. The study shows that the proposed solution and the numerical solution are in good agreement. These solutions are found to be much more favourable for the wall than the conventional solutions. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Continuous gravity recording with Scintrex CG-3M meters:a promising tool for monitoring active zones   总被引：1，自引：0，他引：1  

Sylvain Bonvalot  Michel Diament  & Germinal Gabalda 《Geophysical Journal International》1998,135(2):470-494

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Velocity model estimation for depth imaging: Comparison of three tomography methods on a 2D real data set     

Soazig Le Bégat  Hervé Chauris †  Vincent Devaux  Sylvain Nguyen  Mark Noble 《Geophysical Prospecting》2004,52(5):427-438

The estimation of velocity models is still crucial in seismic reflection imaging as it controls the quality of the depth‐migrated image, which is the basis of geological interpretation. Among the numerous existing methods for velocity determination, tomographic methods are very attractive for their efficiency and ability to retrieve heterogeneities of the medium. We present three tomographic methods in order to estimate heterogeneous velocity models from 2D prestack PP reflection data: a traveltime tomography in the time‐migrated domain, a traveltime and slope tomography in the non‐migrated time domain, and a slope tomography in the depth‐migrated domain. The first method (traveltime tomography in the time domain) is based on continuous picked events, whereas the two slope tomographic methods, one in the time domain and the other in the depth domain, are based on locally coherent events, with no assumptions about reflector geometry or the unknown velocity field. The purpose of this paper is not to describe in detail the theoretical basis and implementation of the methods, but to apply and compare their output using the same marine real data set. Based on the estimated velocity models, the migrated images and the common‐image gathers from the three processing routes, the relative strengths and weaknesses of the methods are discussed. Finally, similarities are indicated and potential alternative approaches are proposed.  相似文献   

Les événements de la limite Permien–Trias : derniers survivants et/ou premiers re-colonisateurs parmi les ostracodes du Taurus (Sud-Ouest de la Turquie)The events of the Permian–Trias boundary: last survivors and/or first colonisers among the ostracods of the Taurides (southwestern Turkey)     

Sylvie Crasquin-Soleau  Sylvain Richoz  Jean Marcoux  Lucia Angiolini  Alda Nicora  Aymon Baud 《Comptes Rendus Geoscience》2002,334(7):489-495

Very few data on Early Triassic marine ostracods are available. In most of cases, the data concern the upper part of the Early Triassic. The Çürük da? section, located in the Western Taurides (Turkey), well stratigraphically constrained by conodonts and foraminifera, has been re-sampled for ostracod study. A significant fauna has been discovered in the Late Permian and the levels of the Earliest Triassic (Hindeodus parvus and Isarcicella isarcica staeschei zones). The ostracods of the basis of the Kokarkuyu Fm. are the oldest Triassic forms ever discovered. The occurrence of Palaeocopes in the earliest Triassic and similarity between the Permian and Induan assemblages suggest that the Lower Triassic Çürük da? ostracods represent a survival assemblage after the Permo-Triassic mass-extinction. To cite this article: S. Crasquin-Soleau et al., C. R. Geoscience 334 (2002) 489–495.  相似文献   

Spatial competition and the new governance framework in Mabibi (Maputaland): implications for development     

Sylvain Guyot 《The Geographical journal》2002,168(1):18-32

The evolution of the demarcation of the political territories in South Africa has resulted in spatial competition between political structures, conservation authorities and local communities. The current multi-governance policies are attempting to overcome the problems created by the political structures of the apartheid era – during which time the declaration of natural areas for conservation resulted in forced removals and negative perceptions of conservation. The case study of Mabibi, within the confines of the Maputaland coast, is a typical example that reflects the history of the past and the conflicts of the present.  相似文献   

A possible link between gabbros bearing High Temperature Iddingsite alteration and huge pegmatoid intrusions: The Society Islands, French Polynesia     

Jean-Philippe Clment  Martial Caroff  Patrick Dudoignon  Patrick Launeau  Marcel Bohn  Joseph Cotten  Sylvain Blais  Grard Guille 《Lithos》2007,96(3-4):524-542

This paper reports new field observations and new petrological, textural and geochemical data on two gabbroic intrusions and one pegmatoid dyke from the French Polynesian islands Maupiti and Bora Bora, respectively. Olivine crystals from the Faataufi and Barque de Hiro gabbros (Maupiti) include High Temperature Iddingsite (HTI), exhibiting three distinct morphological facies. Chemical and crystallographical data performed by electron microprobe, scanning microscope, X-ray diffractometry and Near InfraRed spectroscopy show that HTI results from modifications of olivine structure through intense hydroxylation and Fe-oxidation. The HTI-free 120 m-wide Cloche de Hiro dyke (Bora Bora) exhibits a textural zonation from heterogranular/intergranular gabbro (peripheral part) to typical pegmatoid (inner area). We propose a textural tetrahedral classificatory diagram which can be used to clearly distinguish the textural characteristics of the pegmatoids from those of the other coarse-grained samples. Through comparison with a lava flow containing vesicle-rich segregation sheets, we suggest that the Cloche de Hiro dyke may correspond to a huge segregation structure derived from a Maupiti-type HTI-bearing gabbro through a vapor-differentiation process. Both intrusions might be considered as representative of two superposed levels in a vertically arranged magmatic complex. In this view, the Maupiti gabbroic bodies would represent the lower part of the postulated system. Under high oxygen fugacity, olivine crystals would have undergone important modifications of their structure, leading to HTI. The huge Bora Bora pegmatoid dyke would be the upper part of the complex. After expulsion from the HTI-bearing gabbroic solidification zone by build-up of gas pressure, vesicle-rich residual melt would have gathered into a shallow level and crystallized there as a pegmatoid body.  相似文献