线状与面状对象的拓扑关系及其量度指标体系研究

以计算几何模型为基础,结合对人们在相互交流中所涉及的拓扑关系分析,本文将线状与面状要素的拓扑关系概括为19种形式,并建立了15种量化指标对其进行细化描述,给定了这19种拓扑关系与15种量化指标的依赖关系,规范了15种拓扑关系量化指标的应用条件,最后对所提出的拓扑关系及其量化指标模型实施的可行性进行了分析。文中所提的拓扑关系描述深化了GIS平台的信息查询,并对查询语言的改进具有借鉴价值。     

Ecological adaptation of Reaumuria soongorica root system architecture to arid environments

The architectural parameters of Reaumuria soongorica root system in different habitats of Gansu Province, China were analyzed to examine its ecological adaptability to arid environments. Results show that： （1） Topological indices of R. Soongorica root sys- tem are small in all habitats, and root branching pattem tends to be dichotomous. Also, the indices gradually increase in the Min- qin windblown sand region and the Zhangye Gobi region in Hexi Corridor, which indicates that drought tends to produce her- ringbone-like root branching pattems. （2） Fractal dimension values ofR. Soongorica root system are small and not obvious in the Minqin windblown sand region and the Zhangye Gobi region in Hexi Corridor, with values of 1.1778 and 1.1169, respectively. Fractal dimension values are relatively large in Jiuzhoutai semi-arid hilly and gully region of the Loess Plateau, which indicates that the R. Soongorica root system has better fractal characteristics in this region than in the other regions. （3） Total branching ra- tios of the R. Soongorica root system in arid regions of Hexi Corridor are smaller than that in the Jiuzhoutai semi-arid hilly and gully region of the Loess Plateau. This shows that root branching ability in the semi-arid region is stronger, and it decreases to some degree with increased drought. （4） The root connection lengths of R. soongorica root system are long in all habitats, but there are significant length differences between the different habitats. The root connection length at the Minqin windblown sand region is the longest. It is concluded that R. soongoriea adapts to arid environments by decreasing root branching, decreasing root overlap and increasing root connection length, which makes its root branching pattern tend to be herringbone-like to reduce com- petition in root internal environment for nutrients and to enhance root absorption rate of nutrients, and ensure effective nutrition space. Thus the roots can absorb enough water and nutrients in resource-poor settings to ensure normal physiological requirements.     

三维拓扑关系的基本问题和研究进展

三维拓扑关系是三维空间关系中最重要的空间关系,是三维空间数据表达、查询、分析与应用的理论基础,是目前拓扑关系研究的热点。本文从三维空间实体的定义和描述、三维拓扑关系描述、表达与应用等方面回顾了国内外学术界所取得的研究进展,同时分析了存在的一些基本问题。     

A new geospatial overlay method for the analysis and visualization of spatial change patterns using object-oriented data modeling concepts

Traditional geographic information system (GIS)-overlay routines usually build on relatively simple data models. Topology is – if at all – calculated on the fly for very specific tasks only. If, for example, a change comparison is conducted between two or more polygon layers, the result leads mostly to a complete and also very complex from–to class intersection. A lot of additional processing steps need to be performed to arrive at aggregated and meaningful results. To overcome this problem a new, automated geospatial overlay method in a topologically enabled (multi-scale) framework is presented. The implementation works with polygon and raster layers and uses a multi-scale vector/raster data model developed in the object-based image analysis software eCognition (Trimble Geospatial Imaging, Munich, Germany). Advantages are the use of the software inherent topological relationships in an object-by-object comparison, addressing some of the basic concepts of object-oriented data modeling such as classification, generalization, and aggregation. Results can easily be aggregated to a change-detection layer; change dependencies and the definition of different change classes are interactively possible through the use of a class hierarchy and its inheritance (parent–child class relationships). Implementation is exemplarily shown for a change comparison of CORINE Land Cover data sets. The result is a flexible and transferable solution which is – if parameterized once – fully automated.     

The Influences of Thermodynamic Characteristics on Aerodynamic Roughness Length over Land Surface

It has previously been shown that aerodynamic roughness length changes significantly along with nearsurface atmospheric thermodynamic state; however, at present, this phenomenon remains poorly understood, and very little research concerning this topic has been conducted. In this paper, by using the data of different underlying surfaces provided by the Experimental Co-observation and Integral Research in Semi-arid and Arid Regions over North China, aerodynamic roughness length (z₀) values in stable, neutral, and unstable atmospheric stratifications are compared with one another, and the relationship between z₀ and atmospheric thermodynamic stability (ζ) is analyzed. It is found that z₀ shows great differences among the stable, neutral, and unstable atmospheric thermodynamic states, with the difference in z₀ values between the fully thermodynamic stable condition and the neutral condition reaching 60% of the mean z₀. Furthermore, for the wind speed range in which the wind data are less sensitive to z₀, the surface z₀ changes more significantly with ζ, and is highly correlated with both the Monin-Obukhov stability (ζ₀) and the overall Richardson number (R_ib), with both of their correlation coefficients greater than 0.71 and 0.47 in the stable and unstable atmospheric stratification, respectively. The empirical relation fitted with the experimental observations is quite consistent with the Zilitinkevich theoretical relation in the stable atmosphere, but the two are quite distinct and even show opposite variation tendencies in the unstable atmosphere. In application, however, verification of the empirical fitted relations by using the experimental data finds that the fitted relation is slightly more applicable than the Zilitinkevich theoretical relation in stable atmospheric stratification, but it is much more suitable than the Zilitinkevich relation in unstable atmospheric stratification.     

Land scarcity and land access in a hazard-prone island: Sagar,Indian Sundarbans

The analytical inseparability of natural environment and society is reiterated by the findings of this study which contributes to a genre of studies that centre-stages the socio-ecological system. This study seeks to understand the interplay of state-related and other modes of securing property rights in the context of pervasive coastal hazards through a case study from the Indian Sundarbans region (Sagar Island in West Bengal). This paper also contributes to research pertaining to slow-onset disasters and attempts to examine emerging dimensions of land scarcity as well as diverse modes of access to land in the context of progressive ecological vulnerability. The analysis highlights the varying shades of declining land access and investigates how existing land policies and disaster management mechanisms remain far from extending security to communities experiencing environmental crisis. The paper thereby examines how community and state agencies adopting means to allocate property may in fact refute legality and perpetuate informality.     

山区土地多功能性与过渡性地理空间关联分析

以宜宾市长宁县为研究区,基于多源数据,在栅格尺度上量化了土地利用功能。利用景观叠加分析及相关性分析等方法,明确了土地多功能性的空间分异特征,并揭示了土地功能与地形要素之间的地理空间过渡性关联。结果表明：① 山区过渡性地理空间土地生产、生态和生活功能具有多组合性,空间异质性较强。② 长宁县土地多功能性在空间上由北部平原向南部山区过渡递增,多重和双重功能主导的土地主要分布在中部槽谷和南部山区,占土地总面积的50%以上。③ 地形因子对土地多功能景观的形成发挥较大的作用,海拔650 m、地形起伏度200 m、坡度15°是土地利用多功能性的临界值,超过此临界值土地多功能性趋于减少,但生态功能占居主导。     

缅孟边境罗兴亚难民的人口学特征及其对区域地缘政治关系的影响

基于联合国难民署的动态监测数据,对2018年1月至2020年9月期间的缅孟边境罗兴亚难民人口规模、人口结构及其对区域地缘政治关系的影响进行分析。研究表明：1）缅孟边境罗兴亚难民规模大且呈不断增长的态势;女性难民多于男性,难民年龄结构趋于年轻型,以18岁以下的未成年人为主,青壮年难民占总人口比重次之且增长快速;在空间分布上表现出典型的“距缅孟边境的距离衰变规律”,即难民营地向西部扩张,难民规模呈现自东向西递减的分布规律。2）罗兴亚难民的人口规模及结构对区域地缘政治关系产生了显著影响。一是深刻影响着缅甸的民主化进程;二是对缅孟边境安全形成挑战,导致缅孟关系趋于紧张;三是引发了多地缘行为体的介入与关注,进而引发了围绕难民问题的地缘政治博弈,导致东盟内部的分化及其地缘政治的外溢效应。3）相较于部分西方国家及国际组织,中国提出的“三步走”解决方案符合缅孟两国的实际情况,在中缅孟联合工作组机制下,罗兴亚难民问题正朝着合作共商的道路积极推进解决。     

基于事件数据分析法的两岸关系测度及影响因素研究

海峡两岸同根同源,发展两岸关系、推进祖国统一是实现中华民族伟大复兴的必然要求。从政治互动、经贸往来和文旅交流3个维度构建两岸关系综合评价指标体系,利用事件数据分析法和熵值法,对2000—2018年的两岸关系进行定量测度、演化阶段划分及影响因素分析,进而对两岸关系的良性发展提出建议。结果表明：①21世纪以来,两岸关系经历了低谷波动期（2000年1月—2008年5月）、全面发展期（2008年6月—2016年5月）和冷却回落期（2016年6月—2018年12月）,呈现整体周期性、局部突变性的演化特征;②两岸关系主要受区域地缘环境、大陆综合实力、台湾政党轮替以及非传统安全因素等4个方面的影响;③大陆应当持续优化两岸关系地缘环境、继续提升综合实力、推进两岸社会融合以及建立防范非传统安全风险的机制。