DSM辅助下城区大比例尺正射影像镶嵌线智能检测

传统算法以重叠区域色彩(或灰度)差值图像为正射影像镶嵌线检测基础,可以很好地避开色差区域,但对建筑物高密集的城区效果不明显。本文以高精度数字表面模型为检测基础,通过智能识别处理手段对地面区域与非地面区域进行良好区分。传统镶嵌线检测算法都是以迭代运算为基础的智能算法,算法复杂度高。本文发展出一种贪婪蛇型算法,该算法仅与搜索步距、方向旋转间隔、以及重叠区域宽度等三个因素相关,具有速度快,效率高等优点。针对典型的城市区域进行镶嵌线检测实验,结果表明DSM辅助下的城区正射影像镶嵌线能很好地避开房屋等明显地表实体,并且贪婪蛇型算法能有效地进行最优路径检测。     

利用灰集进行空间区域拓扑关系不确定性定量分析

针对不确定性空间区域对象间拓扑关系不确定性的定量分析问题,提出了一种具有双隶属度函数的灰集表示模型,利用双隶属度函数的截集将不确定性空间区域对象转化为确定性区域对,借用相关的不确定性空间拓扑关系定性分析模型,将不确定性空间对象间拓扑关系的不确定性量化为一个可信度区间。     

GOUM:一种基于UML的地理本体模型映射方法研究

针对地理本体模型构建过程中语义数据模型与逻辑数据模型难以实现映射这一关键问题,提出了一种新的映射方法—GOUM映射法。该方法将面向对象UML技术引入地理本体模型,通过分析地理本体模型与UML模型之间的映射关系,设计了一种GOUM映射规则,并用BNF范式对GOUM进行形式化定义,将地理本体中的概念、属性、语义关系等进行抽象、封装、继承,采用GOUM映射规则将其映射为UML模型,同时将产生式推理方法引入该映射中,实现了UML下的地理本体语义推理和共享。     

基于模糊本体的时空数据模型构建方法研究

针对时空推理及信息查询中存在的时空模糊性问题,通过模糊隶属函数对模糊本体中的模糊概念和关系进行描述,在模糊本体5W2H语义概念模型的基础上构建了FGO-5W2HST时空数据模型,研究了本体方法下的时空推理的模糊扩展,并将上述研究应用于旅游景点信息领域,从而对时空推理查询及语义信息检索过程进行模拟验证。     

Rates of Geologic Processes: Problems for an Introductory Geology Course

Geologic processes occur over a range of time scales. Introductory geology courses should provide students with an understanding of earth processes as well as the rates at which these processes operate. Three quantitative problems involving the rate of radioactive decay, the movement of groundwater pollution, and the rate of erosion in the Himalayas are described. These problems require students to graph data, understand units and orders of magnitude, manipulate equations, and put numerical answers into a broader geologic context.     

A capability matching and ontology reasoning method for high precision OGC web service discovery

Finding the right spatially aware web service in a heterogeneous distributed environment using criteria such as service type, version, time, space, and scale has become a challenge in the integration of geospatial information services. A new method for retrieving Open Geospatial Consortium (OGC) Web Service (OWS) that deals with this challenge using page crawling, link detection, service capability matching, and ontology reasoning, is described in this paper. Its major components are distributed OWS, the OWS search engine, the OWS ontology generator, the ontology-based OWS catalog service, and the ontology-based multi-protocol OWS client. Experimental results show that the execution time of this proposed method equals only 0.26 of that of Nutch's method. In addition, the precision is much higher. Moreover, this proposed method can carry out complex OWS reasoning-based queries. It is being used successfully for the Antarctica multi-protocol OWS portal of the Geo-Information Web Service Portal of the Polar.     

A spatio-temporal ontology for geographic information integration

This paper presents an axiomatic formalization of a theory of top-level relations between three categories of entities: individuals, universals, and collections. We deal with a variety of relations between entities in these categories, including the sub-universal relation among universals and the parthood relation among individuals, as well as cross-categorial relations such as instantiation and membership. We show that an adequate understanding of the formal properties of such relations – in particular their behavior with respect to time – is critical for geographic information processing.

The axiomatic theory is developed using Isabelle, a computational system for implementing logical formalisms. All proofs are computer verified and the computational representation of the theory is available online.     

Estimation of earthquake hazard parameters for incomplete and uncertain data files

The maximum likelihood estimation of earthquake hazard parameters (maximum regional magnitudem _max, activity rate , and theb parameter in the Gutenberg-Richter distribution) is extended to the cases of incomplete and uncertain data. The method accepts mixed data containing only large (extreme) events and a variable quality of complete data with different threshold magnitude values. Uncertainty of earthquake magnitude is specified by two values, the lower and upper magnitude limits. It is assumed that such an interval contains the real unknown magnitude. The proposed approach allows the combination of different quality catalog parts, e.g. those where the assignment of magnitude is questionable and those with magnitudes precisely determined.As an illustration of the method, the seismic hazard analysis for western Norway and adjacent sea area (4–8°E, 58–64°N) is presented on the basis of the strongest earthquakes felt during the period 1831–1889 and three complete catalog parts, covering the period 1890–1987.Paper presented at the 21st General Assembly of the European Seismological Commission held in Sofia, 1988.On leave from Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland.