利用城市骨架线网的道路和居民地联动匹配方法

同名道路或者居民地数据间由于数据一致性程度不高,往往存在较大的几何位置偏差,当对道路或者居民地单独进行匹配时,不利于提高匹配正确率和效率。针对这一问题,本文提出了一种利用城市骨架线网的道路和居民地联动匹配方法。联动匹配即模仿人在读图时通过特征地物和空间关联寻找目标地物的思维过程,将匹配看作是一种特征目标寻找、信息关联传递的推理过程。首先,利用约束Delaunay三角网对地图构建城市骨架线网。然后,通过道路、骨架线、骨架线网眼和居民地之间的拓扑关系建立道路和居民地之间的匹配传递模型。最后,根据该传递模型实现通过道路匹配带动居民地匹配或者通过居民地匹配带动道路匹配的联动匹配。该方法优势在于只要有一种要素的数据一致性比较好,就能带动另一种要素取得很好的匹配效果,同时符合人类进行匹配时的认知过程。     

平面拓扑模型的多边形矢量更新算法

为了提高土地利用变更图斑的更新效率,文章提出了一种平面拓扑图模型下的多边形矢量数据更新算法:采用平面拓扑图的数据结构,实现多边形几何对象间的线段求交计算,解决多边形间在重点和重边情况下的几何裁剪问题;通过对底图几何对象与变更几何对象之间拓扑关系的判别,不仅能够检测出矢量底图数据中发生变化的几何信息,而且可以减少几何运算的次数,提升矢量数据的更新效率。实验结果表明该算法具有良好的适用性及较高的更新效率。     

1∶10000 DLG中高压线与铁塔点一致性自动处理方法的研究

为提高处理1∶10 000 DLG中高压线与铁塔点不一致性问题的工作效率,提出了两种方法:基于网络分析的高压线与铁塔点一致性自动处理;基于空间关系的高压线与铁塔点一致性自动处理。以某一测区内2 248条高压线与10 379个铁塔点作为实验数据,实验结果表明,本文提出的方法与人工处理相比在保证质量的前提下还极大地提高了工作效率。     

A comparative study of nonlinear Markov chain models for conditional simulation of multinomial classes from regular samples

Simulating fields of categorical geospatial variables from samples is crucial for many purposes, such as spatial uncertainty assessment of natural resources distributions. However, effectively simulating complex categorical variables (i.e., multinomial classes) is difficult because of their nonlinearity and complex interclass relationships. The existing pure Markov chain approach for simulating multinomial classes has an apparent deficiency—underestimation of small classes, which largely impacts the usefulness of the approach. The Markov chain random field (MCRF) theory recently proposed supports theoretically sound multi-dimensional Markov chain models. This paper conducts a comparative study between a MCRF model and the previous Markov chain model for simulating multinomial classes to demonstrate that the MCRF model effectively solves the small-class underestimation problem. Simulated results show that the MCRF model fairly produces all classes, generates simulated patterns imitative of the original, and effectively reproduces input transiograms in realizations. Occurrence probability maps are estimated to visualize the spatial uncertainty associated with each class and the optimal prediction map. It is concluded that the MCRF model provides a practically efficient estimator for simulating multinomial classes from grid samples.     

安徽省新石器和夏商周时代遗址时空分布与人地关系的初步研究

安徽省新石器早期遗址有淮北的小山口和江南的沟汀,该时期淮河流域的聚落多于长江流域。新石器中期,考古发掘的野生动物骨骼和孢粉分析表明聚落周围是一个河湖密布、森林草原并存的生态环境。新石器晚期,古人已能分辨土壤的优劣并很可能会利用环境条件改善土壤的不良特性;蒙城尉迟寺遗址的剖面分析表明,环境只是古聚落分布和数量变化的基础因素,生产力的因素也在起作用,因为长时间的持续降温和夏初的大洪水侵袭。夏商周时期全省聚落总数增加,但淮北平原因为长时间的持续降温和夏初的大洪水侵袭,聚落大规模缩减。皖中和皖南的丘陵山地地貌使那里所受洪灾较轻,灾后这些地区因热量条件好使聚落迅速发展起来。新聚落大多建在利于农业生产、能躲避洪水的地方。     

用16S rDNA序列初步探讨部分真虾类的系统发育关系

利用DNA序列测定技术测定了真虾下目7科8个种的线粒体16S rDNA部分序列,与从GenBank检索得到的12个相关种的16S rDNA部分序列进行同源性比对,探讨其系统发育关系及16S rDNA在真虾类系统发育研究中的应用。比对序列长353bp,其中变异位点221个、简约信息位点180个。碱基转换替代速度比颊换替代速度慢。以螯虾下目的Austropotamobius pallipes为外群构建了这20种真虾的系统发育关系分支图,结果展示：（1）长臂虾科隐虾亚科的Awhistus custos远离长臂虾亚科分支。而且它的16S rDNA序列在Genbank中,首先与六足纲（Hexapoda）的昆虫比对上。（2）长臂虾科长臂虾亚科的两个近缘属Palaemon和Palaemonetes问的4个种混合相聚,说明传统形态分类中以大颚有无触须作为这两个属的属级形态鉴定特征尚需进一步审定。（3）鼓虾总科藻虾科的Exhippolysmata ensirostris与褐虾总科褐虾科的Crangon affinis处在同一分支,而没与鼓虾科的种类形成姐妹群。研究结果表明,16S rDNA片段的序列很适合研究真虾类的属间系统发育关系,而在研究属上高级阶元或种下阶元间的系统发生关系时较不敏感,因其变异对于种级水平显得过于保守,而对于科级以上阶元又显得太快。     

土与结构间接触面的非线性弹性-理想塑性模型及其应用

将非线性弹性理论与弹塑性理论相结合,对于土与结构间接触面提出了一种非线性弹性-理想塑性模型,用于模拟土与结构相互作用体系的变形与破坏机理。推导建立了这种接触面单元的应力-应变关系和弹塑性系数矩阵,并且讨论了这种模型在基坑开挖与支护分析应用中所面临的数值计算问题。最后针对某一基坑工程实例,应用这种接触面模型进行了数值计算与分析,结果表明,该模型能够较合理地模拟接触面上的变形机理与受力状态。     

论地理学面临的挑战与发展

地理科学研究地球表层系统特定时空层次下的系统有序度和变化。其发展正面临着几大挑战:①地球表层系统的复杂性难以精确定量描述;②人地关系变化速度超过人类认识与预警能力;③地球表层系统的模糊性与科学价值精确性存在矛盾;④地理学与其它学科的竞争剧烈;21世纪地理学研究主要趋势:①地理学研究人文化;②界面研究将成为自然地理研究热点;③全球研究是地理学重大题材;④地理学研究生态化;⑤山地研究将成为地理学重大领域;为着地理学的顺利发展,建议:①造就地理学思想家和战略家;②进行地理学方法论的集成和创新;③寻找适合各时代认识水平的定量化方法;④重点突出与人类命运攸关的重大课题,创立有震撼性、权威性的理论和成果。     

宁夏北部地区土地覆盖模式及其发展潜力

With the objectives to acquire the fundamental data of the territorial resource,understand the impacts of human activities on the lan use and cover patterns and evaluate the potential of the future exploitation,and intensive land cover classification with and accuracy of 93?has been completed for North Ningxia by remote sensin technique based on the adoption of a combination method composed of texture training,maximum likelihood classification and post-processing such as re-allocation and aggregation.This classification result was incorporated with the contemporaneous socio-economic and meteorological data for cross-sectional regression modelling to reveal the spatial determinants of the land cover patterns and understand the human-environmental relationships.A tentative evaluation on the potential of soil exploitation in the near future was carried out in combination with our land use and cover change detection results aiming at supplying some useful references for the central and local governments in their sustainable land use planning.     

Storage‐discharge relationships at different catchment scales based on local high‐precision gravimetry

In hydrology, the storage‐discharge relationship is a fundamental catchment property. Understanding what controls this relationship is at the core of catchment science. To date, there are no direct methods to measure water storage at catchment scales (10¹–10³ km²). In this study, we use direct measurements of terrestrial water storage dynamics by means of superconducting gravimetry in a small headwater catchment of the Regen River, Germany, to derive empirical storage‐discharge relationships in nested catchments of increasing scale. Our results show that the local storage measurements are strongly related to streamflow dynamics at larger scales (> 100 km²; correlation coefficient = 0.78–0.81), but at small scale, no such relationship exists (~ 1 km²; correlation coefficients = ?0.11). The geologic setting in the region can explain both the disconnection between local water storage and headwater runoff, and the connectivity between headwater storage and streams draining larger catchment areas. More research is required to understand what controls the form of the observed storage‐discharge relationships at the catchment scale. This study demonstrates that high‐precision gravimetry can provide new insights into the complex relationship between state and response of hydrological systems. Copyright © 2012 John Wiley & Sons, Ltd.