Caractérisation sous système d'information géographique des incendies de forêts : l'exemple du Liban.

Cette étude a été conduite dans le contexte de la définition d'une stratégie de défense contre les incendies au Liban. On a procédé à la création d'un système de gestion des incendies par circonscription foncière. L'analyse statistique et spatiale (sous SIG) des données recueillies sur les incendies au cours d'une période de 20 ans (1983-2003) nous a permis d'établir des cartes de récurrence des feux, de définir les types de peuplements les plus affectés et de déterminer la période critique et les causes probables de leur occurrence

The application of GIS based decision-tree models for generating the spatial distribution of hydromorphic organic landscapes in relation to digital terrain data

Accurate information about organic/mineral soil occurrence is a prerequisite for many land resources management applications (including climate change mitigation). This paper aims at investigating the potential of using geomorphometrical analysis and decision tree modeling to predict the geographic distribution of hydromorphic organic landscapes in unsampled area in Denmark. Nine primary (elevation, slope angle, slope aspect, plan curvature, profile curvature, tangent curvature, flow direction, flow accumulation, and specific catchment area) and one secondary (steady-state topographic wetness index) topographic parameters were generated from Digital Elevation Models (DEMs) acquired using airborne LIDAR (Light Detection and Ranging) systems. They were used along with existing digital data collected from other sources (soil type, geological substrate and landscape type) to explain organic/mineral field measurements in hydromorphic landscapes of the Danish area chosen. A large number of tree-based classification models (186) were developed using (1) all of the parameters, (2) the primary DEM-derived topographic (morphological/hydrological) parameters only, (3) selected pairs of parameters and (4) excluding each parameter one at a time from the potential pool of predictor parameters. The best classification tree model (with the lowest misclassification error and the smallest number of terminal nodes and predictor parameters) combined the steady-state topographic wetness index and soil type, and explained 68% of the variability in organic/mineral field measurements. The overall accuracy of the predictive organic/inorganic landscapes' map produced (at 1:50 000 cartographic scale) using the best tree was estimated to be ca. 75%. The proposed classification-tree model is relatively simple, quick, realistic and practical, and it can be applied to other areas, thereby providing a tool to facilitate the implementation of pedological/hydrological plans for conservation and sustainable management. It is particularly useful when information about soil properties from conventional field surveys is limited

Multitemporal unsupervised classification and NDVI to monitor land cover change in Lebanon (1987-1998) Environmental monitoring in the South-Eastern Mediterranean region using RS/GIS techniques Chania : CIHEAM Options Méditerranéennes : Série B. Etudes et

To cite th is article / Pou r citer cet article -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Abstract: Three Landsat TM-images of different dates (June of 1987(June of , 1994(June of , and 1998 were analyzed to detect the land cover changes that have been occurred in two chosen sites (Hermel area and Dahr El Baidar area) in Lebanon. The images were registered for possible spatial comparison and were atmospherically corrected using ATCOR2 of the software ERDAS-IMAGINE for further analytical processes. A hybrid approach was carried out between the multitemporal unsupervised classification and the vegetation index differencing to simplify the search for change and no change pixels. The classification was performed on 12 bands images, i.e., the bands 1, 2, 3, 4, 5 and 7 were generated twice in the image, to obtain the possible land cover changes and discard what is not clear or what is due to cloud effect. A threshold value, the mean plus the double of the standard deviation, was applied on the NDVI-image differentiation to obtain the first change image for each year relative to the reference one (1987 image). The multitemporal unsupervised classified images were matched with the change images to resolve areas where change in land cover took place. Both positive and negative changes in the land cover were observed and analyzed for their type of change. Land rehabilitation for agriculture in Hermel area appeared to be more than 70 ha in 1998. However, the excavation in Dahr El Baidar for the same year reached around 165 ha

Caractérisation sous système d'information géographique des incendies de forêts : l'exemple du Liban.

International audienceCette étude a été conduite dans le contexte de la définition d'une stratégie de défense contre les incendies au Liban. On a procédé à la création d'un système de gestion des incendies par circonscription foncière. L'analyse statistique et spatiale (sous SIG) des données recueillies sur les incendies au cours d'une période de 20 ans (1983-2003) nous a permis d'établir des cartes de récurrence des feux, de définir les types de peuplements les plus affectés et de déterminer la période critique et les causes probables de leur occurrence

Erosion hydrique des sols dans les milieux méditerranéens: une revue bibliographique

National audienc

Use of the OASIS structural classification system for mapping the landscape units in a representative region of Lebanon

National audienc

Impact des activités humaines sur l'érosion hydrique des sols dans la région côtière montagneuse du Liban

National audienc

Human practices influencing hydric erosion in Mount Lebanon

International audienc

Caractérisation morpho-pédologique des zones karstiques du Liban: sensibilité des sols à l'érosion hydrique

National audienc