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排序方式: 共有104条查询结果,搜索用时 203 毫秒
91.
基于DEM生成小比例尺分省彩色晕渲图   总被引:2,自引:0,他引:2  
分析了基于DEM数据的自动晕渲生成的意义 ,介绍了我国 1∶2 5万DEM数据库的结构 ,同时在对 1∶2 5万DEM重采样生成多尺度空间数据的基础上生成晕渲图片 ,比较、分析并提出了相关的参考建议  相似文献   
92.
本文在分析地图集符号系统设计特点的基础上,提出了地图集符号“系统构成”的概念;进而,讨论了与地图集符号系统构图有关的因素;最后,应用地图符号理论对地图集符号系统的构图规律进行了研究。  相似文献   
93.
A series of balanced cross-sections across the Sub-Atlas thrust belt and the northern Ouarzazate basin are used to illustrate the structural geometry and the timing of deformation at the southern front of the High Atlas Mountains of Morocco. The selected area is among the best sedimentary records of mountain building of the entire orogenic system. The study of the relationships between thrusts and synorogenic continental formations enables the unraveling of kinematic sequences and the proposal of a relative chronology of deformation. Active thrusting in the area occurred in a rather continuous fashion from the Oligocene to the Pliocene, punctuated by a major erosional phase imprecisely placed in late Oligocene to early Miocene times. Detrital sedimentary facies indicate that uplift in the hinterland of the High Atlas, to the north of the Sub-Atlas belt, was taking place already by mid Eocene times, although it might have commenced locally even earlier. Within the Sub-Atlas zone, the exposed faults did not propagate in a simple piggy-back fashion but show evidence of a complex, synchronous sequence with events of fault reactivation and out-of-sequence thrusting.  相似文献   
94.
95.
The South Middle Atlas front constitutes a northeast-trending shear zone, located north of the Neogene Missour basin and east of the Taza Guercif basin. This paper analyses the Southern Middle Atlas Fault Zone (SMAFZ) deformation since the Pliocene. The set of structures observed suggests that reverse and thrust faulting along the central part of the SMAFZ are combined with left-lateral slip along N–S striking faults of its south-western termination and right-lateral faulting along E–NE striking faults of the east–northeast termination. Thrusts and oblique thrust-related anticlines of the two lateral ramps partly accommodate north-west directed motion of the African plate. The Thrusts probably resulted from rejuvenation of Jurassic normal faults; they were active during the Upper Miocene–Pliocene and the Pleistocene. The geometries of positive inversion structures and buttressing effects are clearly dependent on the geometry and sedimentology of the original basin-controlling fault system and on the presence of a décollement level. Field mapping is integrated with Landsat imagery and a digital elevation model to investigate the morphotectonic evolution of the south-eastern range front of the Middle Atlas. Geomorphological features provide significant information on the processes that govern lateral propagation of active anticlines. Both suggest that the deformation front may have been active since Pliocene.  相似文献   
96.
《湖北省县级行政区域界线详图集》的编制与实现   总被引:1,自引:0,他引:1  
本文对《湖北省县级行政区域界线详图集》的编制目的、意义进行了概述,对图集的技术方案、设计原则进行了介绍,对编制过程中出现的难点问题进行了分析,并提出了解决方案。  相似文献   
97.
《Comptes Rendus Geoscience》2018,350(6):289-298
Because of its location in the boundary zone between the Anti-Atlas and the Atlas–Meseta crustal domains of Morocco, the Mougueur Paleozoic Massif is a key area to decipher the evolution of the Gondwana NW margin during the Paleozoic. In this work, we report for the first time the occurrence of Hirnantian sandstones, Silurian (Gorstian) graptolitic shales and probable Lower Devonian turbidites in the Massif. Comparison of our observations with regional stratigraphic data from literature allows us to suggest that the area was included in the distal part of the West African Craton passive margin during Cambrian-Devonian times.  相似文献   
98.
This paper presents the first analysis of the diversity of regulating ecosystem services (ESS)—key variables for global environmental sustainability and change in an urban era—across a globally important part of the urban world, urban Europe. We map the first pan-European pattern of regulating ecosystem services in urban core areas and their associated hinterlands and discuss data against the background of each city's land-use development history and planning culture. Upon selecting more than 300 cities, we used the Urban Atlas database and a straightforward calculation method to map three regulating ecosystem services. The main results of this study show (a) a heterogeneous distribution of regulating ecosystem services across European cities, (b) considerable provisioning differences between core cities and the hinterland, (c) a grouping of European regions according to their potential for urban ecosystem service provisioning and (d) an ecosystem services supply ranking for European cities. Considerable differences in urban ecosystem services were found among northern countries, such as Sweden and Finland, which are rich in supplying ecosystem services compared to the UK and Belgium, which, similar to Spanish and Greek cities, are characteristically low in ecosystem services provision. Our results provide the first overall picture of regulating services in urban EU-Europe and serve to inform decisions on the key aspects of future European policy and strategies involving urban nature, green spaces and health.  相似文献   
99.
Résumé

Un suivi hydrogéochimique saisonnier du Lac Ifrah (Maroc) a été réalisé au cours des années 2003–2006 dans le but de caractériser son fonctionnement hydrogéochimique vis-à-vis des impacts climatiques et anthropiques. Le Lac Ifrah a beaucoup régressé au cours de la dernière décennie. Les eaux sont relativement alcalines, oxygénées, assez turbides et sursaturées en alcalino-terreux. La charge particulaire est moyennement élevée. Le faciès hydrogéochimique est généralement de type bicarbonaté chloro-sodique magnésien. Le lac a connu un déficit hydrique important sous l'effet de la récurrence des sécheresses et de la forte pression anthropique au cours des trois dernières décennies. Ceci s'est traduit par l'élévation de la salinité des eaux impliquant une augmentation de la conductivité électrique et des teneurs en alcalins (Na+ et K+) et en chlorures. Ce déficit est évalué également par la diminution des teneurs en alcalino-terreux (Ca2+ et Mg2+) à la suite de leur précipitation sous forme de carbonates endogéniques. Les indices de saturation vis-à-vis de la calcite, de l'aragonite et de la dolomite sont toujours supérieurs à zéro. L'augmentation des éléments nutritifs (phosphore et nitrates) et la dégradation de l'oxygénation des eaux reflètent l'accélération de l'eutrophisation du lac qui est reflétée aussi par l'augmentation de la charge particulaire et la turbidité des eaux.

Editeur Z.W. Kundzewicz

Citation Etebaai, I., Damnati, B., Raddad, H., Benhardouz, H., Benhardouz, O., Miche, H. et Taieb, M., 2012. Impacts climatique et anthropique sur le fonctionnement hydrogéochimique du Lac Ifrah (Moyen Atlas marocain). Hydrological Sciences Journal, 57 (3), 547–561.  相似文献   
100.
ABSTRACT

Four models of increasing complexity were tested and compared to simulate snow water equivalent at the local scale in the Moroccan High Atlas range. A classical temperature index model (TI) and three enhanced temperature index models that respectively include the potential clear-sky direct radiation (HTI), the incoming solar radiation (ETI-A) and net solar radiation (ETI-B), were subjected to annual and multi-annual calibration and cross-validated over the period 2003–2010. When calibrated yearly, the ETI models could be better transferred to other years, whereas all models, including the simple TI model, showed good transferability when calibrated over a longer period that includes inter-annual climate variability. No strong and recurrent relationships emerged between yearly calibrated model parameters and annual climate conditions. However, strong parameter compensation was observed for the enhanced models, which can be explained partly by the collinearity of air temperature and solar radiation causing equifinality of model parameters.  相似文献   
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