地缘政治理论演变与北极航线地缘政治理论假设

北极航线问题因为北冰洋的融化预期加快,而变得愈来愈重要。中国在这一问题上不能失去话语权,要争得北极航线问题国际机制上的主动权,需要对北极航线的地缘政治理论进行深入研究,为成功争取北极航线权益提供理论依据。对地缘政治理论,特别是国外的地缘政治理论进行了阶段划分和系统评价;分析了北极航线问题的特殊性,认为沿用已有的地缘政治理论,不能够清晰描述北极航线的政治地理格局,并且也对我国的北极航线权益争取不利;提出了北极航线地缘政治理论的假设前提,为建立我国的北极航线地缘政治理论体系奠定基础;最后提出了我国关于北极航线问题的四项地缘政治策略,为我国争取北极航线地缘政治地位提供思路和具体措施。     

MODIS影像的局地云量信息元数据提取算法与应用

云对于光学遥感影像质量及其反演地表参数精度有着重要影响,且其作为时空多变要素之一,在一定程度上制约了光学遥感影像的应用。对于具有2 330km的大扫描幅宽MODIS影像而言,现有的元数据标准仅能反映影像的总体云量,而无法反映云的空间分布状况,限制了MODIS数据的局地研究和应用。本文在现有遥感影像元数据标准的基础上,提出了新的元数据项--局地云量,用于反映云在条带影像中的空间分布状况,并实现在MODIS二级云掩膜条带产品(MOD35)中针对特定区域的局地云量信息提取算法。经验证,本算法能较快速和准确地提取省级行政区的局地云量信息,并可根据用户的需求进一步推广到任意指定的多边形区域,为MODIS数据在局地研究和应用提供了便利。     

二维空间关系定性表达模型的研究

通过对几种典型的定性表达模型的分析及比较,论述了单一模型实现空间查询所存在的局限,提出利用组合模型来表达空间关系的方法。最后结合空间查询中的实例,通过介绍如何同时运用二值拓扑关系模型和符号空间索引模型来实现同时包含拓扑关系和方向关系的复杂空间查询来说明这种方法。     

GIS and remote sensing integration for environmental applications

Abstract

The combined use of remotely-sensed images and vector GIS data has received considerable interest in recent years. This review article discusses the historical move towards closer integration of remote sensing and GIS technologies and the requirements of integrated software systems to enable remotely-sensed data to be combined with vector datasets for maximum effect. The benefits of integration to users of both GIS and remote sensing for environmental applications are reviewed and some thoughts are given on terminology and future directions in this field.     

Modeling uncertainty of moving objects on road networks via space–time prisms

Moving objects produce trajectories, which are typically observed in a finite sample of time‐stamped locations. Between sample points, we are uncertain about the moving objects's location. When we assume extra information about an object, for instance, a (possibly location‐dependent) speed limit, we can use space–time prisms to model the uncertainty of an object's location.

Until now, space–time prisms have been studied for unconstrained movement in the 2D plane. In this paper, we study space–time prisms for objects that are constrained to travel on a road network. Movement on a road network can be viewed as essentially one‐dimensional. We describe the geometry of a space–time prism on a road network and give an algorithm to compute and visualize space–time prisms. For experiments and illustration, we have implemented this algorithm in MATHEMATICA.

Furthermore, we study the alibi query, which asks whether two moving objects could have possibly met or not. This comes down to deciding if the chains of space–time prisms produced by these moving objects intersect. We give an efficient algorithm to answer the alibi query for moving objects on a road network. This algorithm also determines where and when two moving objects may have met.     

Mapping transit‐based access: integrating GIS,routes and schedules

Seabed sediment textural parameters such as mud, sand and gravel content can be useful surrogates for predicting patterns of benthic biodiversity. Multibeam sonar mapping can provide near-complete spatial coverage of high-resolution bathymetry and backscatter data that are useful in predicting sediment parameters. Multibeam acoustic data collected across a ～1000 km² area of the Carnarvon Shelf, Western Australia, were used in a predictive modelling approach to map eight seabed sediment parameters. Four machine learning models were used for the predictive modelling: boosted decision tree, random forest decision tree, support vector machine and generalised regression neural network. The results indicate overall satisfactory statistical performance, especially for %Mud, %Sand, Sorting, Skewness and Mean Grain Size. The study also demonstrates that predictive modelling using the combination of machine learning models has provided the ability to generate prediction uncertainty maps. However, the single models were shown to have overall better prediction performance than the combined models. Another important finding was that choosing an appropriate set of explanatory variables, through a manual feature selection process, was a critical step for optimising model performance. In addition, machine learning models were able to identify important explanatory variables, which are useful in identifying underlying environmental processes and checking predictions against the existing knowledge of the study area. The sediment prediction maps obtained in this study provide reliable coverage of key physical variables that will be incorporated into the analysis of covariance of physical and biological data for this area.     

Route planning and cost analysis for travelling through the Arctic Northeast Passage using public 3D GIS

To plan undeveloped optimal routes between Asia and Europe via the Arctic Northeast Passages using a 3D geographic information system (GIS), voyage paths are simulated in a 3D visual form. This ensures that the distances are calculated accurately, and that other voyage data such as water depths, sea ice distribution, and seashore topology are also easily deciphered, giving a more direct and clear demonstration compared to simplified presentations on an Electronic Chart Display & Information System (ECDIS). This article also implements a higher-geometry maze router in ice zone areas to obtain the optimal path in relation to safety and costs. This article compares the optimal Arctic Northeast Passages with traditional routes through the Suez Canal for dynamic analyses of the cost efficiency (including time costs, fuel costs, and other factors) of travel between major ports in Asia and Europe. The average benefit assessment is around 30–45% in a bulk carrier comparison. Thus, a 3D GIS can easily obtain and demonstrate safe navigation routes, providing a very convenient tool for initial planning.     

对1970云南通海地震参数、伤亡、公布形式质疑的商榷

1970云南通海大地震造成15 621人丧生,是1949年建国以来仅次于唐山地震与汶川地震死亡人数最多的地震。由于在特定历史时期发生的地震,因而在社会上对这个地震的情况产生了质疑,质疑最终的结果是贬低本次地震的部分工作,这与过去所做的结论有冲突,就此,本文就质疑的地名、震级、伤亡人数及公布方式等相关问题,从文献与档案资料进行调查研究和分析,回复质疑并对历史真实情况及事件发生的原委得出结论。     

基于语义类型本体的地名组配查询

地名查询方式多种多样,但它们都没有考虑地名语义类型因素,而语义类型恰恰是地名信息中相当重要的一部分。以地名语义分类为基础,构建了地名语义类型本体模型,并以郑州市为例进行了地名组配查询实验。结果表明,该方式对于检索地名的相关信息具有较好的辅助作用,为地名查询与检索作了有益的补充。     

PATHCLUST在聚落遗址空间模式研究中的应用

本文主要讨论PATHCLUST算法的原理和方法,给出了聚类分析选择最优算法应注意的问题;以郑州地区仰韶文化聚落遗址空间模式研究为例,讨论了PATHCLUST算法在聚落遗址空间模式研究中的应用。结果表明,此算法可有效揭示聚落遗址的空间分布结构规律。