导航地理框架数据建模与实现技术初探——基于基础地理数据的道路网络构建     

黄蔚  刘丽芬  蒋捷  赵勇  王桂芝 《地理信息世界》2007,5(5):58-65

导航地理框架数据是导航地理数据的基础,是集成导航应用的交通信息与服务信息的空间定位框架。导航地理框架数据的特点在于描述与表达道路网络的连通关系。它在表达和组织方式方面与传统的基础地理数据有较大区别。本文通过分析现有基础地理数据中道路信息表达的特点,研究了导航地理框架数据的内容与拓扑表达,提出了基于基础地理数据的导航地理框架数据道路网络构建方法。  相似文献   

Hydrographic conditions in the Tsushima Strait revisited   总被引：1，自引：1，他引：0  

Tomoharu Senjyu  Shigeaki Matsui  In-Seong Han 《Journal of Oceanography》2008,64(2):171-183

Long-term averaged temperature and salinity distributions in the Tsushima Strait are investigated on the basis of a concurrent dataset of the eastern and western channels during 1971–2000. Both temperature and salinity show a clear seasonal variation with weak and strong stratifications in December–April and June–October, respectively. The largest standard deviations occur in summer around the thermocline for temperature and in the surface layer for salinity. This indicates large interannual variability in the development of a thermocline and low salinity water advection from the East China Sea. The water masses in both channels are distinctly different from each other; the water in the western channel is generally colder and fresher than that in the eastern channel throughout the year. Baroclinic transport based on the density distributions shows a seasonal variation with a single peak in August for the eastern channel and double peaks in April and August for the western channel. However, this cannot explain the seasonal variation in the total volume transport estimated from the sea level differences across the channels. The spatial distribution of baroclinic transport shows a year-round negative transport towards the East China Sea behind the Iki Island in the eastern part of the eastern channel. This negative transport reflects the baroclinic structure between the offshore Tsushima Current Water and cold coastal water. The corresponding southwestward currents are found in both Acoustic Doppler Current Profiler (ADCP) and high frequency (HF) radars observations.  相似文献   

A New Understanding of Channel Patterns and Facies Models of the Shallow Lake Delta Facies of Fuyu Oil Reservoir in Songliao Basin,China     

LI Yanping  CHEN Shumin  SONG Yongzhong  ZHANG Erhua  SHEN Jiagang  ZHENG Jianbin 《《地质学报》英文版》2008,82(3):596-609

In the Fuyu Reservoir of Songliao Basin, there occur a series of well-developed peculiar shallow lake delta facies, which can be divided to such three ones as the upper delta plain subfacies, the lower delta plain subfacies, and the delta front subfacies. Among them the upper delta plain subfacies mainly grows proximal distributary channels; the lower delta plain subfacies mainly grows distal ones. The entire Fuyu Reservoir has mainly developed 7 kinds of distributary channel patterns： proximal/ distal meandering type distributary channels, proximal/distal low-sinuosity type distributary channels, proximal/distal straight type distributary channels, and subaqueous distributary channels. Among these patterns, the proximal and distal meandering type distributary channels have bigger thickness of point bar and better sorting and low content of mud; moreover, they are the major reservoirs and occur in the bottom of Quan-4th member. The sandbars of the subaqueous distributary channels have higher mud content, and serve as the poorer reservoirs, and mainly occur in the top of Quan-4th member.  相似文献   

开茂水库工程岩溶勘察     

郭建平 《中国勘察设计》2011,(6):89-91

开茂水库区岩溶发育十分复杂,发育程度在空间分布上和规模上具有差异性,在时间上形成多期次岩溶,众多影响岩溶发育的因素相互影响、相互作用。准确、完全地查明库区岩溶现象,几乎不可能,建议在重点处理已经查明的岩溶通道的基础上,预留一定的工作量,待水库蓄水后,根据蓄水后实际情况,在必要情况下进行局部、重点处理。  相似文献   

下刚果盆地深水沉积中新统层序划分及其控制因素     

张笑  王振奇  李士涛  刘启亮  李健 《海洋地质前沿》2011,(10):27-33

对于具有较宽陆架的下刚果盆地,当相对海平面下降时期,陆架区沉积中心向外陆架迁移,形成陆架边缘三角洲.其为深水区提供大量陆源碎屑物质,使低位体系域发育碎屑流沉积、浊流水道及前端扇体系;当相对海平面上升时期,沉积中心后退至内/中陆架,使深水区海侵十高位体系域以深海、半深海原地泥质沉积及泥质碎屑流沉积为主.深水层序以凝缩层段...  相似文献   

Adjustment and recovery of unstable alluvial channels: Identification and approaches for engineering management   总被引：2，自引：0，他引：2  

Andrew Simon 《地球表面变化过程与地形》1995,20(7):611-628

The management of riverine environments is shown to require a knowledge and awareness of the complex interactions between fluvial and mass-wasting processes, riparian vegetation, and channel form. Identification of the cause of instability rather than the local symptoms, and knowledge of the temporal and spatial aspects of channel adjustment are central to the application of (1) appropriate analyses to estimate future channel changes, (2) appropriate mitigation measures, and (3) the protection of river-crossing structures and adjacent land. Conceptual models of channel evolution and bank-slope development are particularly valuable for interpreting past and present processes, applying appropriate computational techniques to estimate future channel changes, and implementing strategies to mitigate the impacts of processes likely to dominate the channel in the future. Techniques for identification and analysis of channel instability are interdisciplinary and provide a mechanism for estimating changes in channel-bed elevation and channel width with time. Features of channel form and associated riparian vegetation can be used as diagnostic criteria to identify channel processes, the stage of channel evolution and the magnitude and extent of instability. Changes in bed elevation with time can be represented using an exponential function; changes in channel width with time can be calculated using slope stability equations and (or) projection of a temporary angle of stability from a low-angle surface termed the ‘slough line’ that supports re-establishment of woody vegetation. These techniques, in combination with knowledge of the state of channel evolution, can then be used to assess the appropriateness of various mitigation measures to control on-going channel adjustments and to protect river-crossing structures.  相似文献   

The multivariate controls of hydraulic geometry: A causal investigation in terms of boundary shear distribution     

He Qing Huang  Robin F. Warner 《地球表面变化过程与地形》1995,20(2):115-130

Most downstream hydraulic geometry exponents have been found to be very close to the classic values reported by Leopold and Maddock (1953). These have been viewed as the simplified cases to general trends because the hydraulic geometry of alluvial channels is actually the product of ‘multivariate controls’ (Richards, 1982). This paper is an attempt to develop a soundly based foundation for the explanation of the physical mechanisms of these controls. A quantitative relationship between channel shape and boundary shear distribution developed from experimental flume results is found to be applicable in some instances to alluvial channels, particularly to stable canals. On the basis of this relationship, it is shown that downstream hydraulic geometry is determined not only by flow discharge, but also by channel slope, channel average roughness and sediment composition of the channel boundary. This is strongly supported by our analysis of 529 observations from both stable canals and natural rivers in the U.S.A. and the U.K. The difference between regime relations in canals and the hydraulic geometry of rivers appears to be caused mainly by channel slope and average roughness, which can be regarded as constants only in stable canals. The close relationship between discharge and channel average roughness observed in canals is not repeated in natural channels, partly because of the variety of flow values used to define the channel-forming discharge. Furthermore, it is indicated that the effects of the sediment composition of the channel boundary on hydraulic geometry are significant and need further investigation.  相似文献   

云南楚雄盆地西部浅水风暴岩与珊瑚条砾灰岩的成因   总被引：2，自引：0，他引：2  

韩征  余素玉 《地球科学》1989,14(6):593-598

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Improvements in long-core measurement techniques: applications in palaeomagnetism and palaeoceanography     

Robin Weeks  Carlo Laj  Lionel Endignoux  Michael Fuller  rew Roberts  René Manganne  Erick Blanchard  William Goree 《Geophysical Journal International》1993,114(3):651-662

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Modeling solute transport in river channels using dispersion theory     

T. Morales-Juberias  P. Zafra  M. Olazar  I. Antigüedad  I. Arrate 《Environmental Geology》1994,24(4):275-280

Carrying out a series of field tracer experiments in river channels allows recognition of river behavior in different flow conditions and thus investigation of the evolution of a solute, tracer, or pollutant over the range of flow rates considered. In this paper, data from tracing tests conducted on the Artibai River in northern Basque Country are used to demonstrate the approach. In all experiments the tracer used was lithium and it was added to the river as an input pulse. An analytical solution to the instantaneous injection model that accounts for the effective initial amount of tracer injected, calculated from the tracer breakthrough curve, instead of the conventional initial injection concentration, is used. The technique is applied to estimate travel times, Péclet numbers, and dispersion coefficients using an optimization algorithm with the aim of characterizing the tracer movement in the stream and analyzing its evolution. Subsequently, considering the results of various tracer experiments, conducted over different flow rates, empirical relationships between dispersion, velocity, and flow rates may be determined. This information allows characterization of the river behavior and can be used to model transportation and dispersion of a tracer or pollutant.  相似文献