Analysis of Interaction and Co‐editing Patterns amongst OpenStreetMap Contributors

OpenStreetMap (OSM) is a very well known and popular Volunteered Geographic Information (VGI) project on the Internet. In January 2013 OSM gained its one millionth registered member. Several studies have shown that only a small percentage of these registered members carry out the large majority of the mapping and map editing work. In this article we discuss results from a social‐network based analysis of seven major cities in OSM in an effort to understand if there is quantitative evidence of interaction and collaboration between OSM members in these areas. Are OSM contributors working on their own to build OSM databases in these cities or is there evidence of collaboration between OSM contributors? We find that in many cases high frequent contributors (“senior mappers”) perform very large amounts of mapping work on their own but do interact (edit/update) contributions from lower frequency contributors.     

Understanding the potential relationship between the socio-economic variables and contributions to OpenStreetMap

OpenStreetMap (OSM) has seen an exponential increase in the last few years and large volumes of geodata have been received from volunteered individuals. The collected geodata are heterogeneous in terms of different dimensions such as spatial patterns of contributions, quality, patterns of contributing individuals, and type of contributions. Because contributors’ personal information is anonymously stored by the OSM administrators, alternative methods are needed to investigate the role of contributors’ characteristics on their mapping behavior. This study is intended to explore the potential socio-economic characteristics of contributors in highly contributed areas to have better insights about the latent patterns of involved individuals in a highly dynamic state of the most active country in OSM, Germany. A logistic regression model (LRM) is applied to discover the potential correlations between dependent and independent variables. The findings explain that the areas with high population density, middle level of education, high income, high rate of overnight stays, high number of foreigners, and residents aged from 18 to 69 are more likely to be involved in OSM. Furthermore, the degree of dynamism in OSM is a function of proximity to built-up areas. Finally, concluding remarks concerning the independent variables and model sensitivity are presented.     

Modeling aggregated expertise of user contributions to assess the credibility of OpenStreetMap features

The emergence of volunteered geographic information (VGI) during the past decade has fueled a wide range of research and applications. The assessment of VGI quality and fitness‐of‐use is still a challenge because of the non‐standardized and crowdsourced data collection process, as well as the unknown skill and motivation of the contributors. However, the frequent approach of assessing VGI quality against external data sources using ISO quality standard measures is problematic because of a frequent lack of available external (reference) data, and because for certain types of features, VGI might be more up‐to‐date than the reference data. Therefore, a VGI‐intrinsic measure of quality is highly desirable. This study proposes such an intrinsic measure of quality by developing the concept of aggregated expertise based on the characteristics of a feature's contributors. The article further operationalizes this concept and examines its feasibility through a case study using OpenStreetMap (OSM). The comparison of model OSM feature quality with information from a field survey demonstrates the successful implementation of this novel approach.     

User Contribution Patterns and Completeness Evaluation of Mapillary,a Crowdsourced Street Level Photo Service

Mapillary is a Web 2.0 application which allows users to contribute crowdsourced street level photographs from all over the world. In the first part of the analysis this article reviews Mapillary data growth for continents and countries as well as the contribution behavior of individual mappers, such as the number of days of active mapping. In the second part of the analysis the study assesses Mapillary data completeness relative to a reference road network dataset at the country level. In addition, a more detailed completeness analysis is conducted for selected urban and rural areas in the US and part of northern Europe for which the completeness of Mapillary data will also be compared with that of Google Street View. Results show that Street View provides generally a better coverage on almost all road categories with some exceptions for pedestrian and cycle paths in selected cities. However, Mapillary data can be conveniently collected from any mobile device that is equipped with a photo camera. This gives Mapillary the potential to reach better coverage along off‐road segments than Google Street View.     

地图数据图层级批量综合功能的设计与研制

目前,已有地图综合系统使用过程中需要专业人员深度参与,耗时耗力、自动化程度较低。针对这一问题,从软件工程的角度探讨了图层级批量综合功能的研制。以1∶5万居民地图层数据的综合处理为例,分别从建筑物目标的剖分、特征参量定义与计算、综合操作决策与实施、综合控制规则建立与表达4个方面进行分析,尝试构建"特征诊断→行为决策→操作执行"的完整技术链条。结合样例数据对提出的技术设想进行可行性验证,并对后续工作进行展望。     

Development of a Speech-Based Augmented Reality System to Support Exploration of Cityscape

When people explore new environments they often use landmarks as reference points to help navigate and orientate themselves. This research paper examines how spatial datasets can be used to build a system for use in an urban environment which functions as a city guide, announcing Features of Interest (FoI) as they become visible to the user (not just proximal), as the user moves freely around the city. Visibility calculations for the FoIs were pre‐calculated based on a digital surface model derived from LIDAR (Light Detection and Ranging) data. The results were stored in a text‐based relational database management system (RDBMS) for rapid retrieval. All interaction between the user and the system was via a speech‐based interface, allowing the user to record and request further information on any of the announced FoI. A prototype system, called Edinburgh Augmented Reality System (EARS), was designed, implemented and field tested in order to assess the effectiveness of these ideas. The application proved to be an innovative, ‘non‐invasive’ approach to augmenting the user's reality.     

Analyzing the effect of earthquakes on OpenStreetMap contribution patterns and tweeting activities

ABSTRACT

Natural disasters, such as wildfires, earthquakes, landslides, or floods, lead to an increase in topical information shared on social media and in increased mapping activities in volunteered geographic information (VGI) platforms. Using earthquakes in Nepal and Central Italy as case studies, this research analyzes the effects of natural disasters on short-term (weeks) and longer-term (half year) changes in OpenStreetMap (OSM) mapping behavior and tweet activities in the affected regions. An increase of activities in OSM during the events can be partially attributed to those focused OSM mapping campaigns, for example, through the Humanitarian OSM Team (HOT). Using source tags in OSM change-sets, it was found that only a small portion of external mappers actually travels to the affected regions, whereas the majority of external mappers relies on desktop mapping instead. Furthermore, the study analyzes the spatio-temporal sequence of posted tweets together with keyword filters to identify a subset of users who most likely traveled to the affected regions for support and rescue operations. It also explores where, geographically, earthquake information spreads within social networks.     

卫星大地测量学的研究现状及发展趋势

机载海洋激光测深系统发射的激光脉冲经由大气、海气界面和海水的复杂信道传播, 信号功率随海水深度的增加呈指数衰减, 同时脉冲波形随深度增加发生严重的脉冲展宽与波形失真, 此两类传输特性分别限制了最大测量深度与测深精度。为了在确保最大测量深度指标的前提下改进机载海洋激光测深系统的测深精度, 首先结合实测水质数据与蒙特卡罗仿真方法, 研究不同深度下的回波信号特性, 揭示激光信号的传输特性, 建立新的激光测深系统参数设计方法, 可满足国际上现有机载海洋激光测深系统的指标; 然后在系统参数确定的条件下, 对不同深度回波信号的波形失真进行仿真, 设计了自适应匹配滤波算法以提高测深精度。仿真结果表明, 所设计的系统参数及自适应匹配滤波算法可以实现机载测绘性能为白天测深深度50 m、测深精度166 mm, 夜晚测深深度70 m、测深精度172 mm。     

卫星大地测量学的研究现状及发展趋势

从全球国际地球参考框架（International Terrestrial Reference Frame,ITRF）的建立、维护与发展,卫星测高、卫星重力等的发展及应用,全球卫星导航系统（Global Navigation Satellite System,GNSS）、卫星激光测距（Satellite Laser Ranging,SLR）、甚长基线干涉测量（very Long Baseline Interferometry,VLBI）、卫星多普勒定轨定位（Doppler Orbitography by Radiopositioning Integrated on Satellite,DORIS）的融合应用,海洋测绘和室内定位的发展等几个方面综述了大地测量学及卫星导航定位技术的最新进展,并提出中国2000国家大地坐标系与自主卫星导航系统的主要应用及发展目标。     

Assessing the Completeness of Bicycle Trail and Lane Features in OpenStreetMap for the United States

This article assesses the completeness of bicycle trail and on‐street lane features in OpenStreetMap (OSM). Comparing OSM cycling features with reference data from local planning agencies for selected US Urbanized Areas shows that OSM bicycle trails tend to be more completely mapped than bicycle lanes. Manual evaluation of mapped cycling features in OSM and Google Maps for selected test areas within the Central Business Districts of Portland (OR) and Miami (FL) through comparison with governmental datasets, satellite imagery, and Google Street View, shows that the Bicycle layer in Google Maps can help to identify some missing or erroneously mapped OSM cycling links. However, Google Maps was also found to have some gaps in its data layers, suggesting that consultation of current trail and lane data from local planning authorities, if available, should be considered as an additional data source for bicycle related planning projects.     

关于地理信息系统未来发展的思考

在Geographic Information System(GIS)近60年的发展演进中,理论和技术都取得了长足的进步;应用领域扩大到社会的方方面面,社会影响力越来越大;体系结构、开发模式和服务模式等都发生了深刻的变化。为了推动GISystem进一步向前发展,在综述GIS中之“S”的三种含义即System（系统）、Science（科学）和Service（服务）以及GIS近60年来取得的丰硕成果的基础上,重点就以下三个问题进行了讨论：（1）如何认识地理信息系统（GISystem）。首先解析地理信息系统的三个关键词（系统、信息、地理信息）,据此论述了地理信息系统的内涵,分析了地理信息系统同地图、计算机地图制图、地图数据库的关系,认为地理信息系统源于又超越了地图、计算机地图制图和地图数据库,并认为地理信息系统具有装备的特性。（2）地理信息系统是怎样发展演进的。重点分析了由“地理信息系统”到“地理信息服务”的发展演进的社会需求背景、技术背景、学科背景,从应用领域、数据资源和功能的扩展及体系结构、开发模式和服务模式等方面,分析了地理信息系统发展演进的主要表现。（3）地理信息系统的未来发展将走向...     

浅谈移动测量系统未来发展

随着移动测量系统的不断发展,人们越来越关注该系统。本文主要通过介绍移动测量系统的组成和工作原理,分析了该系统与传统测量方式相比所具有的优点,并结合当前移动测量技术在地理空间数据采集中的应用,对未来移动测量技术的发展进行了展望。     

天文导航标准体系建设现状与未来发展

天文导航是利用对自然天体的测量来确定自身位置和航向的导航技术.通过分析天文导航技术的发展现状和应用领域,梳理了国内外天文导航技术的相关标准,给出了天文导航技术的一种标准体系,并对天文导航制定的标准未来发展提出了建议.     

石油行业GIS技术应用现状与展望

重点介绍了国内外石油行业勘探、开发、生产、管道运输、炼油、化工和市场营销等主要业务领域地理信息系统技术的应用情况,并对石油行业地理信息系统的主要发展趋势进行了展望。     

台湾测量事业发展之过程现况及未来

从台湾测量事业的最初起步，发展经历，目前现状与未来发展等方面作了详细阐述，并试图通过台湾测量事业的发展历程说明台湾城市发展对测量的应用与技术的要求。     

Contributions to a quality description of areal objects in spatial data sets

In this paper, we present a quality evaluation of two-dimensional building acquisition. We propose methods for identification and quantification of differences between independently acquired regions, and we present a systematic classification of those differences. Differences between acquired sets R_j={r_i}_j of region r_ij depend on the context of observation, on the technique of observation, etc. We distinguish topological and geometrical differences. Topological differences refer to the interior structure of a set of regions as well as to the structure of the boundary of a single region. Geometrical differences refer to the location of the boundary of a single region or of a set of regions, independent of their representation and of the structure of the boundaries.Identification of differences requires a matching of two data sets R₁ and R₂, which is done here by weighted topological relationships. For the identification of topological differences between two sets R₁ and R₂ of regions, we use the two region adjacency graphs (RAGs). For an identification of geometrical differences, we use the zone skeleton between two matched subsets r_p1 and r_q2 of the given sets. The zone skeleton is labeled with the local distances of the corresponding boundaries of the subsets; especially, we investigate its density function. An example based on two real data sets of acquired ground plans of buildings, shows the feasibility of the approach.     

地理信息系统(GIS)在油气勘探开发中的应用

地理信息系统(GIS)的空间数据管理、空间分析及图形可视化表达方面的功能使其在油气勘探开发中具有广阔的发展前景。本文论述了GIS在石油行业专题制图、盆地模拟、油气资源勘探开发管理及油气资源评价等方面的应用,阐述了GIS在油气勘探开发中的地位和作用,展望了GIS在油气勘探中的应用前景。     

测绘情结(下)——记中国科学院资深院士陈述彭先生

3 超越门户 1954年,他当时在中科院地理研究所,正值参加黄河流域规划,需要大比例尺地图.但当时国家测绘局还没有成立,没有可利用的地图,于是他就主持编绘我国的1∶25万地形图.他编的这套地形图与众不同,怎么不同呢?即山区的等高线是20米,而平原的等高线是2.5米.这在现在看来也都是难以理解的,其难度是很难想像的.因为他觉得,如果平原的等高线是20米的话,黄河口海拔是0米,郑州海拔为95米,整个华北平原也就三条等高线就够了,对经济建设和老百姓来说,根本不够用,于是他将平原的等高线改为2.5米.现在看来这是很古怪的一套图.