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Issuescouverture du solLandLibrary Resource
There are 2, 240 content items of different types and languages related to couverture du sol on the Land Portal.

couverture du sol

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Displaying 1753 - 1764 of 1964

effective approach for land-cover classification from airborne lidar fused with co-registered data

Journal Articles & Books
Décembre, 2012

Airborne lidar provides accurate height information of objects on the earth and has been recognized as a reliable and accurate surveying tool in many applications. In particular, lidar data offer vital and significant features for urban land-cover classification, which is an important task in urban land-use studies. In this article, we present an effective approach in which lidar data fused with its co-registered images (i.e.

Land-cover classification of an intra-urban environment using high-resolution images and object-based image analysis

Journal Articles & Books
Décembre, 2012
Brésil

Detailed, up-to-date information on intra-urban land cover is important for urban planning and management. Differentiation between permeable and impermeable land, for instance, provides data for surface run-off estimates and flood prevention, whereas identification of vegetated areas enables studies of urban micro-climates. In place of maps, high-resolution images, such as those from the satellites IKONOS II, Quickbird, Orbview and WorldView II, can be used after processing.

Variation in NDVI values with change in spatial resolution for semi-arid savanna vegetation: a case study in northwestern South Africa

Journal Articles & Books
Décembre, 2013
Afrique du Sud
Afrique australe

Natural vegetation and crop-greening patterns in semi-arid savannas are commonly monitored using normalized difference vegetation index (NDVI) values from low spatial resolution sensors such as the Advanced Very High Resolution Radiometer (AVHRR) (1 km, 4 km) and Moderate Resolution Imaging Spectroradiometer (MODIS) (250 m, 500 m). However, because semi-arid savannas characteristically have scattered tree cover, the NDVI values at low spatial resolution suffer from the effect of aggregation of near-infrared and red energy from adjacent vegetated and non-vegetated cover types.

Estimating Spatial Variability in Atmospheric Properties over Remotely Sensed Land Surface Conditions

Journal Articles & Books
Décembre, 2008

This paper investigates the spatial relationships between surface fluxes and near-surface atmospheric properties (AP), and the potential errors in flux estimation due to homogeneous atmospheric inputs over heterogeneous landscapes. A large-eddy simulation (LES) model is coupled to a surface energy balance scheme with remotely sensed surface temperature Ts as a key boundary condition. Simulations were performed for different agricultural regions having major contrasts in Ts, canopy cover, and surface rough- ness z0 between vegetated/irrigated and bare soil areas.

Is cellular automata algorithm able to predict the future dynamical shifts of tree species in Italy under climate change scenarios? A methodological approach

Journal Articles & Books
Décembre, 2011
Italie

In this paper is presented a methodological approach which integrates statistic modelling and 2-D cellular automata (CA) in order to describe tree species shifts responding to the climate changes foreseen for Italy in the 21st century. Five Italian tree species populations of Abies alba, Pinus sylvestris, Fagus sylvatica, Acer campestris and Quercus suber and their actual potential distributions (PDs) – represented by Importance Value (IV), have been considered.

Evaluating Source Area Contributions from Aircraft Flux Measurements Over Heterogeneous Land Using Large-Eddy Simulation

Journal Articles & Books
Décembre, 2013

The estimation of spatial patterns in surface fluxes from aircraft observations poses several challenges in the presence of heterogeneous land cover. In particular, the effects of turbulence on scalar transport and the different behaviour of passive (e.g. water vapour) versus active (e.g. temperature) scalars may lead to large uncertainties in the source area/flux- footprint estimation for sensible (H) and latent (LE) heat-flux fields.

Assessment of sediment connectivity from vegetation cover and topography using remotely sensed data in a dryland catchment in the Spanish Pyrenees

Journal Articles & Books
Décembre, 2014

PURPOSE: Many Mediterranean drylands are characterized by strong erosion in headwater catchments, where connectivity processes play an important role in the redistribution of water and sediments. Sediment connectivity describes the ease with which sediment can move through a catchment. The spatial and temporal characterization of connectivity patterns in a catchment enables the estimation of sediment contribution and transfer paths. Apart from topography, vegetation cover is one of the main factors driving sediment connectivity.

Surface energy fluxes over El Reno, Oklahoma, using high-resolution remotely sensed data

Journal Articles & Books
Décembre, 2003

Accurate estimation of spatial distributions of evapotranspiration (ET) is a goal sought by hydrologists, agronomists, and meteorologists but is difficult to achieve. The usual approaches to estimating ET employ remote sensing observations and a surface energy flux model. However, resolution of remote sensing data, needed to observe patterns of biophysical variables, is commonly too coarse (>1 km) to distinguish between land cover types that constrain ET. Accuracy of ET estimates can be improved by using higher- resolution (

Patterns and trends in land-use land-cover change research explored using self-organizing map

Journal Articles & Books
Décembre, 2011

Research on land change has a long history, has generated numerous publications and continues to receive international research attention. To facilitate the understanding of the patterns and trends of land-change research, this article uses a content-based text-retrieval approach and self-organizing map to analyse more than 700 peer-reviewed remote-sensing and natural-science papers on land-use/cover change (LUCC) from the past two decades. We present the results in map-like displays and discuss papers within the identified clusters to examine the research activities.

Changing Landscapes for Forest Commons: Linking Land Tenure with Forest Cover Change Following Mexico’s 1992 Agrarian Counter-Reforms

Journal Articles & Books
Décembre, 2013
Mexique

Mexico’s 1992 agrarian counter-reforms opened up the country’s vast network of common property regimes, known as ejidos, to the possibility of privatization. This study investigates the relationship between dynamic common property regimes and deforestation in the wake of policy reform among eight ejidos in southeastern Mexico. Using institutional analyses, land use/land cover change (LULCC) analyses and a Forest Dependency Index, we examine how land tenure arrangements relate to land use and forest cover change patterns.

remote sensing approach to monitor the conservation status of lacustrine Phragmites australis beds

Journal Articles & Books
Décembre, 2013
Italie

Phragmites australis populations in native areas have been gradually declining since the mid-20th century. We developed a logical approach based on remote sensing to monitor the conservation status of P. australis beds in response to environmental gradients and orient future management actions in Lake Garda (northern Italy). During the 2010 growing season we collected data on: (i) the structural and functional status of seven P.

Water Scarcity in the Andes: A Comparison of Local Perceptions and Observed Climate, Land Use and Socioeconomic Changes

Journal Articles & Books
Décembre, 2013
Colombie
Amérique du Sud

In the Andean region of South America, understanding communities’ water perceptions is particularly important for water management as many rural communities must decide by themselves if and how they will protect their micro-watersheds and distribute their water. In this study we examine how Water User Associations in the Eastern Andes of Colombia perceive water scarcity and the relationship between this perception and observed climate, land use, and demographic changes. Results demonstrate a complex relationship between perceptions and observed changes.