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PORTAIL D'INFORMATION GÉOGRAPHIQUE

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  • Coexistence conflictuelle aux portes de la ville de Mexico : un ancien pueblo et une enclave sécurisée
  • Analyse d'un conflit entre les anciens habitants d'un village situé dans une zone boisée en périphérie de Mexico, et les nouveaux habitants de classes sociales élevées installés dans une enclave sécurisée. Celle-ci a été construite sur des terrains
  • 2012
  • Tripoli. Les territoires squattés sont illicitement édifiés sur des terrains privés et prennent aussi la forme de bâtiments occupés par des ménages ne disposant d'aucun titre juridique. Les populations résidant dans ces territoires, dont le plus ancien
  • religieuses et politiques. Cependant, pour les enfants âgés de moins de cinq ans, les résultats ont montré des prévalences élevées d'infections diarrhéiques, de fièvre et de toux. Les diarrhées accompagnées de fièvre sont corrélées à la qualité de l'eau
  • 2012
  • Mass elevation effect and its forcing on timberline altitude
  • Altitudinal zonation ; Base level ; Concept ; Eurasia ; Impact ; Latitude ; Longitude ; Mass elevation ; Model ; Mountain ; Multiple regression ; Tree line
  • The concept of mass elevation effect (massenerhebungseffect, MEE) was introduced by A. de Quervain about 100 years ago. It has been usually completely neglected in developing fitting models of timberline elevation, with only longitude or latitude
  • considered as impacting factors. This paper tries to quantify the contribution of MEE to timberline elevation. Considering that the more extensive the land mass and especially the higher the mountain base in the interior of land mass, the greater the mass
  • elevation effect, this paper takes mountain base elevation (MBE) as the magnitude of MEE. The AA. collect 157 data points of timberline elevation, and use their latitude, longitude and MBE as independent variables to build a multiple linear regression
  • equation for timberline elevation in the southeastern Eurasian continent. The results show that MBE, serving as a proxy indicator of MEE, is a significant factor determining the elevation of alpine timberline.
  • 2012
  • Coastal environment ; Digital elevation model ; Geographical information system ; Geomorphometry ; Italy ; Karst ; Marine terrace ; Methodology ; Polje ; Puglia ; Quantitative analysis ; Sea level ; Underground water
  • This study aims at defining a general method for identifying, in karst coastal settings, the elevations of flat or low topographic gradient surfaces (using morphometric analysis of Digital Elevation Models (DEMs) and geographical information systems
  • (GISs), and their comparison with elevations of distinctive karstic levels (passages, lateral solution cavities) observed in vertical shafts and horizontal caves. The method is applied to a regional coastal carbonate formation in southern Italy, by using
  • a 10 m DEM and information on 140 complex caves and 85 shafts. Of the 15 elevations above sea level indicated by DEM analysis, 13 match clearly those highlighted by significant frequencies of distinctive karstic levels. These elevations are validated
  • by comparison to the elevation of terraces and karst plains indicated in the literature.
  • 2012
  • Secondary controls of alpine treeline elevations in the western USA
  • The AA. examine data from treelines across the western USA, divided into subregions to elucidate the patterns of these additional constraints. They determined the best predictor of elevation for 930 treeline sites in 26 mountain ranges by finding
  • a climate variable with least variance. They used the variance at each site from this predictor to compute an elevation anomaly that became the dependent variable in correlation and regression analyses. They derived independent variables from digital
  • elevation models and regional climate interpolations. The results show variables related to water and energy play a secondary role. The AA. found that the division of the observations into regions and interpretation of spatial patterns within regions
  • was necessary to interpret the relations between the potential predictor variables and the elevation anomaly.
  • 2012
  • morphology that combines LiDAR topography with spectrally based bathymetry. Water surface elevations extracted from the LiDAR along the water's edge were used to produce a continuous water surface that preserved along-channel variations in slope. Subtracting
  • local flow depths from this surface yielded estimates of the bed elevation that were then combined with LiDAR topography for exposed areas to create a composite representation of the riverine terrain. The accuracy of this terrain model was assessed via
  • comparison with detailed field surveys. A map of elevation residuals showed that the greatest errors were associated with underestimation of pool depths and failure to capture cross-stream differences in water surface elevation.
  • 2012
  • meilleures performances en général que ceux situés dans la même région mais à l'extérieur des villes. Cependant, à l'exception de Bristol, aucune ville ne présente des taux significativement plus élevés que ceux enregistrés dans la région du Sud-Est
  • . On n'associe pas à une localisation urbaine d'externalités spatiales aussi élevées que dans cette région.
  • 2012
  • L’A. analyse la politique de régularisation foncière à Tijuana au Mexique et ses résultats contrastés en la matière après plusieurs années de pratique. Les quartiers qui se sont développés illégalement et dont la valeur foncière est plus élevée ne
  • présentent pas un taux élevé de régularisation. Il conclut que ce système n’est pas suffisamment bien structuré pour favoriser le marché foncier ou revaloriser les quartiers à faibles revenus.
  • 2012
  • This paper presents a range of geomorphometric analyses of Polish territory using both classical and new approaches. The new approach included the presentation of land relief through standard deviations of relative elevation in regular geometric
  • fields. Maps of hypsometry, elevation difference, angle of slope, exposure and standard deviation were also presented. The survey involved elevation data from the SRTM-3 satellite with a resolution of 3×3' (60-65×90 m), which were converted for research
  • 2012
  • Cantine scolaire ; Choix de l'école ; Concurrence ; Education ; Elève ; England ; Enseignement secondaire ; Géographie sociale ; London ; Royaume-Uni ; Ségrégation sociale
  • L’A .propose les indices de ségrégation dans les quartiers londoniens à partir des critères d’admission mis en place par les établissements sous contrat avec l’Etat et destinés aux élèves du secondaire. Ensuite, il analyse les différences
  • distinguant les écoles secondaires qui procèdent ou non à une sélection. Les résultats montrent qu’il y a une importante proportion d’élèves pouvant accéder gratuitement aux cantines, aussi bien dans les écoles publiques et religieuses. Bien qu’il constate une
  • 2012
  • The nature of erosive rainfall on a tropical volcanic island with an elevated interior
  • On Mauritius, erosive storm events are found to differ markedly between the coastal lowlands and the elevated interior with regard to the frequency, the total rainfall generated, the duration, total kinetic energy, and total erosivity of individual
  • 2012
  • , expressed as freezing and thawing n-factors, vary significantly with vegetation type and hence elevational band, with the lowest values for the forested zone and the highest for non-maritime alpine tundra. Equilibrium modelling carried out for one site
  • in the southern part of the region and one in the northern part illustrates the impacts of the differing n-factors on trends in mean ground surface temperature with elevation. Given the range of air temperatures and n-factors, permafrost is possible throughout
  • the Yukon but higher temperatures southward and stronger lapse rates mean that a lower elevational limit exists in northern British Columbia.
  • 2012
  • California ; Digital elevation model ; Drainage network ; Erosion rate ; LiDAR ; Slope ; Slope dynamics ; Slope exposure ; Slope gradient ; Tectonics ; United States of America
  • Here the AA. quantify hillslope response to tectonic across a threshold landscape in the San gabriel Mountains, California, using an 1 m resolution, LiDAR-derived digital elevation model, high resolution panoramic photographs, and cosmogenic
  • beryllium-10 derived catchment erosion rates. Two distinct trends in hillslope behavior emerge : below and above catchment-mean slopes of 30°. Their results reveal important textural details lost in 10 or 30 m resolution digital elevation models of steep
  • 2012
  • Classification ; Digital elevation model ; Geographical information system ; Geomorphology ; Landscape ; Slovenia ; Typology
  • 2012
  • Air temperature ; China ; Digital elevation model ; Model ; Mountain ; Periglacial features ; Permafrost ; Plateau ; Qinghai ; Spatial distribution ; Tibet
  • Decadal changes in permafrost distribution on the Qinghai-Tibet Plateau (QTP) over the past 50 years (1960-2009) were simulated with a response model that uses data from a digital elevation model, mean annual air temperature (MAAT) and the vertical
  • 2012
  • Digital elevation model ; Fluvioglacial features ; Glacier ; Glacier retreat ; Iceland ; Meltwater ; Moraine ; Space time
  • Glacier recession and landform development in a debris-charged glacial landsystem characterized by an overdeepening is quantified using digital photogrammetry, digital elevation model (DEM) construction and mapping of the Icelandic glacier
  • 2012
  • Alps (The) ; Conceptual model ; Digital elevation model ; Erosion ; Europe ; Fault ; France ; Geological structure ; Gully erosion ; Lithology ; Mountain ; Structural geomorphology ; Switzerland ; Watershed
  • failures mechanisms, and (2) the orientation of the maximum joint frequency, this latter being considered as the direction exploited primarily by erosion and mass wasting processes. The morphostructural analysis was performed using digital elevation models
  • 2012
  • Impacts and uncertainty analysis of elevated temperature and CO2 concentration on wheat biomass
  • 2012
  • British Columbia ; Canada ; Digital elevation model ; Model ; Mountain ; Northwest Territories ; Periglacial features ; Permafrost ; Soil temperature ; Solar radiation ; Spatial distribution ; Vegetation ; Yukon
  • to previous permafrost maps. There are notable differences in detail, however, because the main predictive variable used in the local models is equivalent elevation, which incorporates the effects of gentle or inverted surface lapse rates in the forest zone
  • 2012
  • at altitudes of 285-4700 m were examined. Significant correlations of temperature extremes and elevation included the trends of diurnal temperature range, frost days, ice days, cold night frequency and cold day frequency. Regional trends of growing season
  • sensitivity of climate extremes to elevation in southwestern China in the context of recent warming.
  • 2012