Time filter

Source Type

Villeneuve-la-Rivière, France

Lefebvre A.,SIRS | Cheval J.,Tongji University
2015 Joint Urban Remote Sensing Event, JURSE 2015 | Year: 2015

In this paper, we monitored the urban morphology of the old city of Shanghai and its former foreign concessions from 1985 to 2014. Based on a time-series of Landsat 5, 7 and 8 images, this study used Iteratively Reweighted Multivariate Alteration Detection (IRMAD) analysis to detect land-use modifications from traditional urban pattern to new constructions. Results show that urban transformation mainly started in 1995 and perpetuate at an average rate of 88 ha per year. It also brings out that about 55% of the old urban pattern was modified in 2014. A detailed interpretation highlights the development of modern high-rise buildings, roads and subway networks, green infrastructures but also the conservation of protected historical buildings. © 2015 IEEE. Source

Lefebvre A.,SIRS | Corpetti T.,French National Center for Scientific Research
2015 Joint Urban Remote Sensing Event, JURSE 2015 | Year: 2015

This paper is concerned with monitoring morphological changes in the Beijing inner city using remote sensing. The Beijing inner city contains a huge urban heritage composed of traditional courtyards (shiheyuans) and alleys (hutongs). Since the economic reform in 1978, Beijing as most of Chinese cities experiences a fast urbanization process and has to deal with the pressure of the real estate industry and historic preservation. Based on remote sensing images, we have developed a change detection method able to identify the construction of new high-rise buildings to the expense of the old districts. The results highlight the surface area of high-rise buildings has increased from 18% of Beijing inner city to 60% between 1966 and 2010. This study brings out both methodological and thematic interests: the efficiency of the proposed remote sensing approach to process heterogeneous remote sensing images and the Beijing urban transformation to the expense of the old districts. © 2015 IEEE. Source

Tran A.,CIRAD - Agricultural Research for Development | L'Ambert G.,EID Mediterranee | Lacour G.,EID Mediterranee | Lacour G.,Catholic University of Louvain | And 12 more authors.
International Journal of Environmental Research and Public Health | Year: 2013

The mosquito Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) is an invasive species which has colonized Southern Europe in the last two decades. As it is a competent vector for several arboviruses, its spread is of increasing public health concern, and there is a need for appropriate monitoring tools. In this paper, we have developed a modelling approach to predict mosquito abundance over time, and identify the main determinants of mosquito population dynamics. The model is temperature- and rainfall-driven, takes into account egg diapause during unfavourable periods, and was used to model the population dynamics of Ae. albopictus in the French Riviera since 2008 Entomological collections of egg stage from six locations in Nice conurbation were used for model validation. We performed a sensitivity analysis to identify the key parameters of the mosquito population dynamics. Results showed that the model correctly predicted entomological field data (Pearson r correlation coefficient values range from 0.73 to 0.93). The model's main control points were related to adult's mortality rates, the carrying capacity in pupae of the environment, and the beginning of the unfavourable period. The proposed model can be efficiently used as a tool to predict Ae. albopictus population dynamics, and to assess the efficiency of different control strategies. © 2013 by the authors; licensee MDPI, Basel, Switzerland. Source

Lefebvre A.,SIRS | Corpetti T.,Chinese Academy of Sciences | Courty N.,IRISA
IOP Conference Series: Earth and Environmental Science | Year: 2014

This paper is concerned with morphological change analysis in the old foreign concessions of Shanghai from 1969 to 2010. To that end, we use a series of 17 Landsat TM and Landsat ETM + images on which we estimate some feature parameters. The analysis of the resulting time series enables to isolate changes from traditional constructions to new buildings or gardens. Our results show that 70% of the old urban pattern was converted in modern high-rise buildings and green spaces. Source

Baghdadi N.,IRSTEA | Camus P.,IRSTEA | Beaugendre N.,SIRS | Issa O.M.,University of Reims Champagne Ardenne | And 5 more authors.
Remote Sensing | Year: 2011

The objective of this study is to validate an approach based on the change detection in multitemporal TerraSAR images (X-band) for mapping soil moisture in the Sahelian area. In situ measurements were carried out simultaneously with TerraSAR-X acquisitions on two study sites in Niger. The results show the need for comparing the difference between the rainy season image and a reference image acquired in the dry season. The use of two images enables a reduction of the roughness effects. The soils of plateaus covered with erosion crusts are dry throughout the year while the fallows show more significant moisture during the rainy season. The accuracy on the estimate of soil moisture is about 2.3% (RMSE) in comparison with in situ moisture contents. © 2011 by the authors. Source

Discover hidden collaborations