Towards an Automated Comparison of OpenStreetMap with Authoritative Road Datasets

OpenStreetMap (OSM) is an extraordinarily large and diverse spatial database of the world. Road networks are amongst the most frequently occurring spatial content within the OSM database. These road network representations are usable in many applications. However the quality of these representations can vary between locations. Comparing OSM road networks with authoritative road datasets for a given area or region is an important task in assessing OSM's fitness for use for applications like routing and navigation. Such comparisons can be technically challenging and no software implementation exists which facilitates them easily and automatically. In this article we develop and propose a flexible methodology for comparing the geometry of OSM road network data with other road datasets. Quantitative measures for the completeness and spatial accuracy of OSM are computed, including the compatibility of OSM road data with other map databases. Our methodology provides users with significant flexibility in how they can adjust the parameterization to suit their needs. This software implementation is exclusively built on open source software and a significant degree of automation is provided for these comparisons. This software can subsequently be extended and adapted for comparison between OSM and other external road datasets.     

Transport Capacity Limit of Urban Street Networks

Network transport is an important aspect of geographical information science, transportation, complex networks, etc. Previous studies have shown that the transport capacity of street networks can be enhanced by improving routing algorithms. However, the upper throughput limit of street networks is unknown in detail. This article studies the transport process of networks and finds that any connected network has a maximum throughput depending on the topological and structural properties of the network. Based on this, the maximum throughput of street networks is obtained. Experiments show that when the street network remains unchanged, the maximum throughput of the street network is limited and is dependent on road capacity and average path length, regardless of adopted routing algorithms. Our findings suggest that the throughput of networks can be improved by increasing node capacity or decreasing average path length, but the maximum transport capacity of the network cannot be greater than the ratio of the sum of all the nodes' capacities to the average path length of the network, no matter what routing strategies are adopted. This study is expected to be a starting point for more sophisticated research in network transport, such as evaluating the inherent throughput of an urban street network.     

Opportunities for Use of the Spatial Data Transfer Standard at the State and Local Level

Dramatic changes in the way that spatial data have been collected and processed over that last 20 years is leading to a rethinking and restructuring on the most efficient ways to handle geographical information. These changes are taking place at the federal, state, and local governmental levels with great potential for the private sector as well. The formal adoption of the Spatial Data Transfer Standard (SDTS) as the federal database transfer standard for spatial databases signals a new era in this long chain of developments. It offers more flexible and efficient database transfers than earlier tools, and will become the workhorse for implementing the new National Spatial Data Infrastructure. It offers organizations a standard that will make possible and practical a much wider sharing of databases than is currently being done today. Use of the SDTS presents an opportunity to many organizations to share data more easily and reduce the duplication of expensive spatial database resources.     

Integrated Storage and Querying of Spatially Varying Data Quality Information in a Relational Spatial Database

This article investigates a new, integrated technique for storing and retrieving spatially varying data quality information in a relational spatial database. Rather than storing global data quality statements, the system enables data quality information to be referenced to a spatial framework, individual spatial objects, or even parts of spatial objects. The integrated model, called as RDBMS for Spatial Variation in Quality (RSVQ), allows flexible storage of spatially varying data quality information, and seamless querying irrespective of the underlying storage model. RSVQ is founded on a formal model of relational databases, defining a new derived, polymorphic query operator      to join quality data with spatial data. The      operator is implemented in an extension to SQL as a new WITHQUALITY keyword. A performance evaluation of RSVQ was conducted, using an Oracle Spatial database and a case study of cadastral data for parts of Victoria, Australia. The results of this evaluation demonstrated that the system is practical and efficient for a wide range of queries, as well as indicating the performance trade-offs associated with the different data quality storage models. Using the integrated RSVQ approach provides the potential for a single, consistent, database engine for a wide range of existing and proposed spatial data quality management systems.     

Analytical queries on semantic trajectories using graph databases

This article studies the analysis of moving object data collected by location‐aware devices, such as GPS, using graph databases. Such raw trajectories can be transformed into so‐called semantic trajectories, which are sequences of stops that occur at “places of interest.” Trajectory data analysis can be enriched if spatial and non‐spatial contextual data associated with the moving objects are taken into account, and aggregation of trajectory data can reveal hidden patterns within such data. When trajectory data are stored in relational databases, there is an “impedance mismatch” between the representation and storage models. Graphs in which the nodes and edges are annotated with properties are gaining increasing interest to model a variety of networks. Therefore, this article proposes the use of graph databases (Neo4j in this case) to represent and store trajectory data, which can thus be analyzed at different aggregation levels using graph query languages (Cypher, for Neo4j). Through a real‐world public data case study, the article shows that trajectory queries are expressed more naturally on the graph‐based representation than over the relational alternative, and perform better in many typical cases.     

Towards an Open Source Analysis Toolbox for Street Network Comparison: Indicators,Tools and Results of a Comparison of OSM and the Official Austrian Reference Graph

This article presents a novel open source toolbox for street network comparison based on the Sextante geoprocessing framework for the open source Geographic Information System Quantum GIS (QGIS). In the spirit of open science, the toolbox enables researchers worldwide to assess the quality of street networks such as OpenStreetMap (OSM) by calculating key performance indicators commonly used in street network comparison studies. Additionally, we suggest two new performance indicators for turn restriction and one‐way street comparisons specifically aimed at testing street network quality for routing. We demonstrate the use of this toolbox by comparing OSM and the official Austrian reference graph “Graph Integration Platform” (GIP) in the greater Vienna region.     

A topographically preserved road‐network tile model and optimal routing method for virtual globes

Virtual globes enable the combination of heterogeneous datasets for optimal routing analyses in transportation, environmental ecology, and construction engineering. In this study, considering the advantages of the hierarchical tiling structure and topography of virtual globes, we propose a tile‐based optimal routing method for large‐scale road networks in a virtual globe. This method designs a topographically preserved road‐network tile model by partitioning roads into tiles and constructs the road‐network pyramid from the bottom to the top. During construction, a TileArc is calculated and flagged as the shortest path in a tile. Based on the built road‐network pyramid carrying hierarchical TileArcs, a multi‐level and flexible shortest path query can be executed efficiently. The proposed method is implemented with large road networks with different road grades in a virtual globe. Experimental results verify its validity, efficiency, and exactness. Moreover, the length of the shortest path with surface distance is approximately 1.3 times longer than that with Euclidean distance.     

Detection and correction of inconsistencies between river networks and contour data by spatial constraint knowledge

In the representation of topographic data, the distribution of hydrographic networks should be constrained by the contour model’s landform features. During the integration of topographic databases, however, spatial conflicts may destroy these constraints, generating inconsistencies. This study presents a method to detect and correct inconsistencies between river networks and contour data by spatial knowledge. First, structured terrain features are extracted from the contour-based geometric representation and matching relationships between rivers and contours are constructed based on spatial knowledge of the distribution of rivers and talwegs. We then propose a distance metric for measuring differences and identifying inconsistencies between the matched river and contour features. Three correction approaches are provided for different inconsistency situations, including river adjustment referenced to the contour, contour adjustment referenced to the river and adjustment of both river and contour to middle positions. We apply the proposed method to the integration and maintenance of national topographic infrastructure in order to demonstrate its effectiveness.     

基于空间统计特征的河网结构分类

提出了基于特征因子进行空间数据库河网结构分类的方法和技术。探讨了各种类型河网的特征，阐述了时河网进行分类的因子及河网分类的方法和过程，描述了河网数据的有向图组织厦其分类实验。     

基于多进制小波变换的渐进式纹理图像检索

提出了一种基于多进制小波变换的渐进式纹理图像检索方法，纹理图像的特征通过多进制小波分解结果来描述，用低频子图小波系数标准方差和多进制小波直方图结合相应的相似性距离函数，实现目标图像数据库由粗到精的渐进式检索。通过Bordatz和USC纹理图像数据库来检验本方法的精度和效率，获得了较理想的试验结果。     

一体化测绘技术在城市基础地理信息数据更新中的应用

就一体化测绘技术在基础地理信息数据更新中的应用情况进行了较为全面的分析,简要回顾了一体化测绘技术在数字测绘技术体系建设中的发展过程,分析了内外业一体化与采编一体化和图库一体化技术之间的关系,讨论了内外业一体化技术的变迁,分析了航测采编一体化、图库一体化和集群分布式并行计算等技术在基础地理信息数据更新中的作用。     

面向空间延迟可容忍网络的路由协议仿真研究

随着空间通信的发展和卫星节点的增加,空间DTN网络中卫星节点之间的路由的重要性日益明显,大量复杂的卫星网络路由方案相继提出。针对空间DTN网络具有规律性与可预见性,研究了基于卫星节点运动接触规律 (CGR)路由协议。在ONE仿真实验平台下,对真实卫星网络场景进行了仿真实验,并对比了CGR、Epidemic与Prophet路由协议的性能。实验结果表明,相比于Epidemic与Prophet,CGR在消息交付率、平均延时和网络开销比等方面的性能优越。     

城市基础空间数据建库中一些质量控制方法探讨——以广州市规划局1∶10000城市地图数据建库为例

城市基础空间数据库是城市GIS的核心,而数据质量的高低又是数据库建设成功与否的关键。本文在分析城市空间数据的基本特征、数据的特点以及空间数据库中存在的误差来源基础上,结合广州市1∶10 000城市地图数据建库,详细论述了城市基础空间数据建库中进行质量控制的内容及方法。     

Formal definition of a user-adaptive and length-optimal routing graph for complex indoor environments

Car routing solutions are omnipresent and solutions for pedestrians also exist. Furthermore, public or commercial buildings are getting bigger and the complexity of their internal structure has increased. Consequently, the need for indoor routing solutions has emerged. Some prototypes are available, but they still lack semantically-enriched modelling (e.g., access constraints, labels, etc.) and are not suitable for providing user-adaptive length-optimal routing in complex buildings. Previous approaches consider simple rooms, concave rooms, and corridors, but important characteristics such as distinct areas in huge rooms and solid obstacles inside rooms are not considered at all, although such details can increase navigation accuracy. By formally defining a weighted indoor routing graph, it is possible to create a detailed and user-adaptive model for route computation. The defined graph also contains semantic information such as room labels, door accessibility constraints, etc. Furthermore, one-way paths inside buildings are considered, as well as three-dimensional building parts, e.g., elevators or stairways. A hierarchical structure is also possible with the presented graph model.     

A construction schema for provincial spatial database of China

In order to provide a provincial spatial database, this paper presents a scheme for spatial database construction to meet the needs of China. The objective and overall technical route of spatial database construction are described. The logical and physical database models are designed. Key issues are addressed, such as integration of multi-scale heterogeneous spatial databases, spatial data version management based on metadata and integrative management of map cartography and spatial database.     

EVKG: An interlinked and interoperable electric vehicle knowledge graph for smart transportation system

Over the past decade, the electric vehicle (EV) industry has experienced unprecedented growth and diversification, resulting in a complex ecosystem. To effectively manage this multifaceted field, we present an EV-centric knowledge graph (EVKG) as a comprehensive, cross-domain, extensible, and open geospatial knowledge management system. The EVKG encapsulates essential EV-related knowledge, including EV adoption, EV supply equipment, and electricity transmission network, to support decision-making related to EV technology development, infrastructure planning, and policy-making by providing timely and accurate information and analysis. To enrich and contextualize the EVKG, we integrate the developed EV-relevant ontology modules from existing well-known knowledge graphs and ontologies. This integration enables interoperability with other knowledge graphs in the Linked Data Open Cloud, enhancing the EVKG's value as a knowledge hub for EV decision-making. Using six competency questions, we demonstrate how the EVKG can be used to answer various types of EV-related questions, providing critical insights into the EV ecosystem. Our EVKG provides an efficient and effective approach for managing the complex and diverse EV industry. By consolidating critical EV-related knowledge into a single, easily accessible resource, the EVKG supports decision-makers in making informed choices about EV technology development, infrastructure planning, and policy-making. As a flexible and extensible platform, the EVKG is capable of accommodating a wide range of data sources, enabling it to evolve alongside the rapidly changing EV landscape.     

一种模型驱动空间数据库质量检查平台构建

质量检查是空间数据质量控制的关键环节，空间数据库包括矢量空间数据、专题属性数据及元数据等，质量检查内容繁多。现有空间数据库质检软件往往为某一项目“量身定制”，灵活性低。本文从空间数据库质量特征及其语义表达出发，对空间数据库质检规则进行了分析和研究，提出了空间数据库质检DRST模型，并基于该模型开发构建了一套能够适用于各类空间数据库质检需要的平台软件。该平台已在江西省房地一体确权登记数据库质检、第三次国土调查成果数据库质检、地理国情监测成果数据库质检等项目中得到应用。应用实践表明，平台具备良好的适应性和扩展性，为提高空间数据库质量检查效率、解决质检软件生命周期短等问题提供了有效途径。     

新疆地震应急基础数据的处理和建库

介绍了新疆地震应急基础数据库的构成、数据处理和建库及数据库在地震应急指挥技术系统中发挥的作用等。解决了多源数据的处理和整合、多种数据库之间的协同和关联、海量数据的集成等问题。     

泥石流危险度评价的GIS与专家系统集成方法研究

针对泥石流灾害的特点，提出了泥石流危险度评价的系统集成策略。即泥石流危险度评价集地理信息系统和专家系统为一体，采用公共接口模块的外连式结构进行集成，并具有较好的用户界面和构造特定的应用框架为用户导航，实施的中心环节是组分软件的优选、各组分间转换、访问函数的实现和特定应用框架的构造。通过建立孙胡沟流域的数据库和泥石流危险度评价的知识库，利用集成系统对孙胡沟流域泥石流危险度进行了评价。     

四川大巴山国家地质公园地质遗迹景观数据库平台构建

本文以四川大巴山国家地质公园为例,研究并构建了一套面向地质遗迹资源管理和景观规划辅助为主要目标的数据库管理综合平台.参照《中国国家地质公园建设技术要求和工作指南》(2002),建立了适合研究区地质遗迹景观的分类体系、编码规则和数据库.设计开发了基于SOA的数据库管理平台架构,并通过网络门户集成各项服务.经投入运行表明,...