基于语义的地理信息Web服务发现机制研究

为了解决长久以来服务发现的难题,提出了基于语义的地理信息Web服务发现机制.针对地理信息Web服务语义缺乏的问题,在服务的描述和匹配中引入语义的概念;针对地理信息Web服务质量(QoS)支持不足的问题,在服务的匹配中引入QoS的约束;针对Web服务匹配算法缺乏灵活性的问题,提出多级服务匹配的思想;针对粗糙目录分类(或无...     

基于SuperMap世界电子地图多尺度表达的研究

依据地图感受论和地图符号学原理,结合世界电子地图的显示要求和使用特点,针对世界电子地图中数据分级体系不完善、尺度建立不规范等问题,提出了一套世界电子地图多尺度表达分级体系,重点研究了基于SuperMap数据处理的技术方法、分类分级标准和符号设计理论,设计制作了基于SuperMap多尺度世界电子地图。     

基于ArcGIS的1980西安坐标系到2000国家坐标系的转换研究

分析了2000国家坐标系与WGS-84坐标系的椭球参数及定向参数,通过实验证实了在ArcGIS中采用WGS-84坐标系的大地坐标代替2000国家坐标系的大地坐标的可行性.本文在自编写的程序中,使用不同大地坐标转换的布尔莎公式计算出了1980西安坐标系与2000国家坐标系的7个转换参数,并将该参数输入到AreGIS的坐标转换参数文件中,从而实现矢量数据与栅格数据从1980西安坐标系到2000国家大地坐标系的转换.通过对转换结果进行精度分析,认为可选用控制测区范围的3～5个转换公共点,使用本文所述方法与流程可以满足1∶1 000或更大比例尺图件的坐标系统转换.     

Recent Maps and Atlases — Map Cabinet

Abstract

There is currently a high demand for spatial data usage within web applications. From a technical viewpoint, web services and geoportals aim to fulfil user requirements; however, the current cartographic methods do not satisfy the needs of the end users. The problem is more challenging when the final map contains data from various sources that have various cartographic characteristics; therefore, the vital information might be located under the base map layer. In this paper, we propose the concept of layer priorities as foreground, middle ground or background, and we propose the two following methods to enhance the symbolisation: polygon overlay and colour saturation methods. The results from two case studies show that these methods can satisfy the requirements of the end users.     

Towards a National Atlas of the Netherlands as part of the National Spatial Data Infrastructure

Abstract

This paper is about different worlds, and how we try to unite them. One of these worlds is the world of National Atlases: collections of complex, high-quality maps presenting a nation to the geographically interested. The second is the world of National Spatial Infrastructures: highly organized, standardized and institutionalized large collections of spatial data and services. In the paper, we describe the two worlds and their fundamental differences and we present the theoretical framework in which these worlds could be united. We introduce a test bed we are using to try out the theoretical framework in a real-life use case. In the architecture of that test bed, we introduce a National Atlas Services layer and describe how we have created an Atlas Map Viewer component, using the Open Web Platform. We conclude by commenting on the results thus far and taking a look into future developments.     

Code as Cartography

Abstract

Provincial Atlas of People's Republic of China (Chung hua ien min kung wo kuo fên shêng di t'u chi). 190 x 265 mm. pp. 251 (84 pages of maps). Peking: Map Publishing Society (di t'u ch'u p'an shê), China, Oct., 1974. 6.30 Yuan     

网络地图API在“地理信息系统设计”教学中的应用

本文针对"地理信息系统设计"课程的教学概况,深入分析高校开展"地理信息系统设计"教学改革的目标,阐述目前国内外各种主流的电子地图API,指导和培训学生调用电子地图API的技能与技巧,并将网络地图API应用实践引入到"地理信息系统设计"的课程教学中,促进了"地理信息系统设计"实践教学的改革。将教学研讨和应用实践紧密结合,利用新兴的各种电子地图API促进"地理信息系统设计"教学,具有充分的理论依据和实践意义。     

An integrated heterogeneous web service retrieval via combination of instance- and metadata-based schema matching method

Schema matching is a critical step in the integration of heterogeneous web service, which contains various types of web services and multi-version services of the same type. Mapping loss or mismatch usually occurs due to schema differences in structure and content and the variety in concept definition and organization. Current instance schema matching methods are not mature enough for heterogeneous web service because they cannot deal with the instance data in web service domain and capture all the semantics, especially metadata semantics. The metadata-based and the instance-based matching methods, in the case of being employed individually, are not efficient to determine the concept relationships, which are crucial for finding high-quality matches between schema attributes. In this paper, we propose an improved schema matching method, based on the combination of instance and metadata (CIM) matcher. The main method of our approach is to utilize schema structure, element labels, and the corresponding instance data information. The matching process is divided into two phases. In the first phase, the metadata-based matchers are used to compute the element label similarity of multi-version open geospatial consortium web service schema, and the generated matching results are raw mappings, which will be reused in the next instance matching phase. In the second phase, the designed instance matching algorithms are employed to the instance data of the raw mappings and fine mappings are generated. Finally, the raw mappings and the fine mappings are combined, and the final mappings are obtained. Our experiments are executed on different versions of web coverage service and web feature service instance data deployed in Geoserver. The results indicate that, the CIM method can obtain more accurate matching results and is flexible enough to handle the web service instance data.     

Symbol Store: sharing map symbols for emergency management

Maps are a primary means for supporting information sharing and collaboration in emergency management and crisis situations. While a variety of formalized map symbol standards for emergency contexts exist, they have not been widely adopted by mapmakers. Informal symbol conventions are commonly used within emergency management stakeholder groups, but until now there has not been a flexible mechanism for discovering, sharing, and previewing these symbol sets among mapmakers. In this paper, we describe the design and development of the Symbol Store, a visually enabled, web-based interactive tool intended to help mapmakers share point symbols. The Symbol Store allows users to browse symbols by keyword, category tags, and contributors. It also allows for symbols to be previewed on realistic maps prior to download. An initial prototype of the Symbol Store was evaluated by flood mapping experts from the State of California, and the results of this user study led to multiple refinements now implemented in the public version of Symbol Store located at www.symbolstore.org.