Geographical studies of outdoor activities have increased in recent years with the rise in popularity of these activities worldwide,including in Japan.Volunteered geographic information(VGI)is a key tool for organizin...Geographical studies of outdoor activities have increased in recent years with the rise in popularity of these activities worldwide,including in Japan.Volunteered geographic information(VGI)is a key tool for organizing outdoor activities as it offers a means to determine the locational information and names of places.To evaluate the quality of VGI,geospatial data generated by land survey agencies and other VGI are often utilized as reference data.However,since these reference data may not be available,other methods are necessary to assure the quality of VGI.In this study,we examined five trust indicators based on the inherent characteristics of VGI through an empirical case study.We used mountain names extracted from OpenStreetMap in Japan as data because there were almost no other VGI in the vicinity.As a result,we isolated three trust indicators,namely versions,users,and tag corrections,to examine the thematic accuracy of VGI because these were the only statistically significant indicators.However,we found that the prediction rate of thematic accuracy was very low.To improve thematic accuracy,this study recommends using the most accurate versions,applying correctly given tags,and considering the motivations and characteristics of the VGI contributors.展开更多
This study aims to clarify the characteristics of volunteer activities in times of disaster, while taking into account the influence of the orientation towards information intensity, which is an important feature of c...This study aims to clarify the characteristics of volunteer activities in times of disaster, while taking into account the influence of the orientation towards information intensity, which is an important feature of contemporary Japanese society, and focusing on the volunteer activities for recovery and reconstruction in the disaster-stricken areas of the Great East Japan Earthquake. In modern Japanese society, because volunteer activities are being conducted in a variety of forms, those who wish to volunteer can participate in volunteer activities that suit their own situation. Further, in a highly information-oriented society such as modern Japan, many kinds of information systems can be used to conduct a variety of volunteer activities. Also, know-how concerning the introduction and methods of volunteer activity and recruitment for participants in volunteer activities are introduced using various information media, and there are many volunteer activities to choose from. Therefore, it is possible that through the diversification of volunteer activities, many people become involved in volunteer activities on a long-term basis, using ways of doing so that are possible for themselves.展开更多
In this geo-statistical analysis of change detection,we illustrate the evolution of the built-up environment in Shanghai at the street-block level.Based on two TerraSAR-X image stacks with 36 and 15 images,covering th...In this geo-statistical analysis of change detection,we illustrate the evolution of the built-up environment in Shanghai at the street-block level.Based on two TerraSAR-X image stacks with 36 and 15 images,covering the city centre of Shanghai for the time period from 2008 to 2015,a set of coherence images was created using a small baseline approach.The road network from Open Street Map,a volunteered geographic information product,serves as the input dataset to create street-blocks.A street-block is surrounded by roads and resembles a ground parcel,a real estate property–a cadastral unit.The coherence information is aggregated to these street-blocks for each observation and the variation is analysed over time.An analysis of spatial autocorrelation reveals clusters of similar behaviours.The result is a detailed map of Shanghai highlighting areas of change.We argue that the aggregation and grouping of synthetic aperture radar coherence image information to real-world entities(street-blocks)is comprehensible and relevant to the urban planning process.Therefore,this research is a contribution to the community of urban planners,designers,and government agencies who want to monitor the development of the urban landscape.展开更多
Observations of living organisms by citizen scientists that are reported to online portals are a valuable source of information.They are also a special kind of volunteered geographic information(VGI).VGI data have iss...Observations of living organisms by citizen scientists that are reported to online portals are a valuable source of information.They are also a special kind of volunteered geographic information(VGI).VGI data have issues of completeness,which arise from biases caused by the opportunistic nature of the data collection process.We examined the completeness of bird species represented in citizen science observation data from eBird and iNaturalist in US National Parks(NPs).We used approaches for completeness estimation which were developed for data from OpenStreetMap,a crowdsourced map of the world.First,we used an extrinsic approach,comparing species lists from citizen science data with National Park Service lists.Second,we examined two intrinsic approaches using total observation numbers in NPs and the development of the number of new species being added to the data-set over time.Results from the extrinsic approach provided appropriate completeness estimations to evaluate the intrinsic approaches.We found that total observation numbers are a good estimator of species completeness of citizen science data from US NPs.There is also a close relationship between species completeness and the ratio of new species added to observation data vs.observation numbers in a given year.展开更多
Initiatives that rely upon the contributions of volunteers to reach a specific goal are growing more and more with the success of Web 2.0–interactive applications.Also scientific projects are testing and exploiting v...Initiatives that rely upon the contributions of volunteers to reach a specific goal are growing more and more with the success of Web 2.0–interactive applications.Also scientific projects are testing and exploiting volunteers’collaboration,but the quality of information obtained with this approach is often puzzling.This paper offers a rich overview of many scientific projects where geographic contributions are committed to volunteers,to the aim of defining strategies to improve information quality.By describing real examples of Volunteer Geographic Information(VGI),the contribution establishes a categorization based on the characteristics of the information,tasks,and scopes of the projects.After a discussion on the relationships of categories and VGI quality,the paper analyses techniques to improve the quality of volunteered information according to the moment of its assessment(i.e.,ex ante,ex post,or both with respect to information creation).The paper outlines the main limitations of the different approaches and indicates some guidelines for future developments.展开更多
【目的】掌握体力活动与建成环境特征的关联对主动干预公众健康具有重大意义。【方法】为系统地验证建成环境的移动型体力活动使用效能,根据自发地理信息、体力活动、环境特征等关键词从Web of Science等数据库筛选出31篇描述统计汇报...【目的】掌握体力活动与建成环境特征的关联对主动干预公众健康具有重大意义。【方法】为系统地验证建成环境的移动型体力活动使用效能,根据自发地理信息、体力活动、环境特征等关键词从Web of Science等数据库筛选出31篇描述统计汇报完整的学术论文,对文章信息、样本基本信息、研究分析方法、因变量和自变量信息等内容进行系统梳理,在此基础上对论文结果进行量化荟萃分析。【结果】自然环境、建成环境、社会环境及主观感知环境均与移动型体力活动存在一致的显著相关关系,关联程度因体力活动类型而异。自然环境中,归一化植被指数、绿化空间密度等自上而下的绿化水平与各类体力活动的正相关性最强;建成环境中,道路密度也与移动型体力活动存在一致的显著正相关关系,而便利设施的供给、人行道宽度仅对步行活动有积极的促进作用;除骑行活动外,居住用地密度与步行、跑步及一般体力活动都有显著的正相关关系。【结论】大批量、多尺度、高精度的体力活动自发地理信息有助于研究者客观掌握城市街区体力活动的分布,比较不同建成环境在多种时空尺度下的体力活动访问模式及使用效能,进而构建街区环境特征与体力活动适宜性的关联性模型;基于荟萃分析的发现为城市规划者和政策制定者优化和新建体力活动干预设施提供了使用效能预测的经验模型,有助于更科学合理地建设促进健康行为的人居环境。展开更多
Geographic data and tools are essential in all aspects of emergency management:preparedness,response,recovery,and mitigation.Geographic information created by amateur citizens,often known as volunteered geographic inf...Geographic data and tools are essential in all aspects of emergency management:preparedness,response,recovery,and mitigation.Geographic information created by amateur citizens,often known as volunteered geographic information,has recently provided an interesting alternative to traditional authoritative information from mapping agencies and corporations,and several recent papers have provided the beginnings of a literature on the more fundamental issues raised by this new source.Data quality is a major concern,since volunteered information is asserted and carries none of the assurances that lead to trust in officially created data.During emergencies time is the essence,and the risks associated with volunteered information are often outweighed by the benefits of its use.An example is discussed using the four wildfires that impacted the Santa Barbara area in 20072009,and lessons are drawn.展开更多
文摘Geographical studies of outdoor activities have increased in recent years with the rise in popularity of these activities worldwide,including in Japan.Volunteered geographic information(VGI)is a key tool for organizing outdoor activities as it offers a means to determine the locational information and names of places.To evaluate the quality of VGI,geospatial data generated by land survey agencies and other VGI are often utilized as reference data.However,since these reference data may not be available,other methods are necessary to assure the quality of VGI.In this study,we examined five trust indicators based on the inherent characteristics of VGI through an empirical case study.We used mountain names extracted from OpenStreetMap in Japan as data because there were almost no other VGI in the vicinity.As a result,we isolated three trust indicators,namely versions,users,and tag corrections,to examine the thematic accuracy of VGI because these were the only statistically significant indicators.However,we found that the prediction rate of thematic accuracy was very low.To improve thematic accuracy,this study recommends using the most accurate versions,applying correctly given tags,and considering the motivations and characteristics of the VGI contributors.
文摘This study aims to clarify the characteristics of volunteer activities in times of disaster, while taking into account the influence of the orientation towards information intensity, which is an important feature of contemporary Japanese society, and focusing on the volunteer activities for recovery and reconstruction in the disaster-stricken areas of the Great East Japan Earthquake. In modern Japanese society, because volunteer activities are being conducted in a variety of forms, those who wish to volunteer can participate in volunteer activities that suit their own situation. Further, in a highly information-oriented society such as modern Japan, many kinds of information systems can be used to conduct a variety of volunteer activities. Also, know-how concerning the introduction and methods of volunteer activity and recruitment for participants in volunteer activities are introduced using various information media, and there are many volunteer activities to choose from. Therefore, it is possible that through the diversification of volunteer activities, many people become involved in volunteer activities on a long-term basis, using ways of doing so that are possible for themselves.
基金This work was supported in part by the National Natural Science Foundation of China[grant numbers 61331016 and 41174120].
文摘In this geo-statistical analysis of change detection,we illustrate the evolution of the built-up environment in Shanghai at the street-block level.Based on two TerraSAR-X image stacks with 36 and 15 images,covering the city centre of Shanghai for the time period from 2008 to 2015,a set of coherence images was created using a small baseline approach.The road network from Open Street Map,a volunteered geographic information product,serves as the input dataset to create street-blocks.A street-block is surrounded by roads and resembles a ground parcel,a real estate property–a cadastral unit.The coherence information is aggregated to these street-blocks for each observation and the variation is analysed over time.An analysis of spatial autocorrelation reveals clusters of similar behaviours.The result is a detailed map of Shanghai highlighting areas of change.We argue that the aggregation and grouping of synthetic aperture radar coherence image information to real-world entities(street-blocks)is comprehensible and relevant to the urban planning process.Therefore,this research is a contribution to the community of urban planners,designers,and government agencies who want to monitor the development of the urban landscape.
文摘Observations of living organisms by citizen scientists that are reported to online portals are a valuable source of information.They are also a special kind of volunteered geographic information(VGI).VGI data have issues of completeness,which arise from biases caused by the opportunistic nature of the data collection process.We examined the completeness of bird species represented in citizen science observation data from eBird and iNaturalist in US National Parks(NPs).We used approaches for completeness estimation which were developed for data from OpenStreetMap,a crowdsourced map of the world.First,we used an extrinsic approach,comparing species lists from citizen science data with National Park Service lists.Second,we examined two intrinsic approaches using total observation numbers in NPs and the development of the number of new species being added to the data-set over time.Results from the extrinsic approach provided appropriate completeness estimations to evaluate the intrinsic approaches.We found that total observation numbers are a good estimator of species completeness of citizen science data from US NPs.There is also a close relationship between species completeness and the ratio of new species added to observation data vs.observation numbers in a given year.
文摘Initiatives that rely upon the contributions of volunteers to reach a specific goal are growing more and more with the success of Web 2.0–interactive applications.Also scientific projects are testing and exploiting volunteers’collaboration,but the quality of information obtained with this approach is often puzzling.This paper offers a rich overview of many scientific projects where geographic contributions are committed to volunteers,to the aim of defining strategies to improve information quality.By describing real examples of Volunteer Geographic Information(VGI),the contribution establishes a categorization based on the characteristics of the information,tasks,and scopes of the projects.After a discussion on the relationships of categories and VGI quality,the paper analyses techniques to improve the quality of volunteered information according to the moment of its assessment(i.e.,ex ante,ex post,or both with respect to information creation).The paper outlines the main limitations of the different approaches and indicates some guidelines for future developments.
文摘【目的】掌握体力活动与建成环境特征的关联对主动干预公众健康具有重大意义。【方法】为系统地验证建成环境的移动型体力活动使用效能,根据自发地理信息、体力活动、环境特征等关键词从Web of Science等数据库筛选出31篇描述统计汇报完整的学术论文,对文章信息、样本基本信息、研究分析方法、因变量和自变量信息等内容进行系统梳理,在此基础上对论文结果进行量化荟萃分析。【结果】自然环境、建成环境、社会环境及主观感知环境均与移动型体力活动存在一致的显著相关关系,关联程度因体力活动类型而异。自然环境中,归一化植被指数、绿化空间密度等自上而下的绿化水平与各类体力活动的正相关性最强;建成环境中,道路密度也与移动型体力活动存在一致的显著正相关关系,而便利设施的供给、人行道宽度仅对步行活动有积极的促进作用;除骑行活动外,居住用地密度与步行、跑步及一般体力活动都有显著的正相关关系。【结论】大批量、多尺度、高精度的体力活动自发地理信息有助于研究者客观掌握城市街区体力活动的分布,比较不同建成环境在多种时空尺度下的体力活动访问模式及使用效能,进而构建街区环境特征与体力活动适宜性的关联性模型;基于荟萃分析的发现为城市规划者和政策制定者优化和新建体力活动干预设施提供了使用效能预测的经验模型,有助于更科学合理地建设促进健康行为的人居环境。
基金supported by grants from the US National Science Foundation and the US Army Research Office.
文摘Geographic data and tools are essential in all aspects of emergency management:preparedness,response,recovery,and mitigation.Geographic information created by amateur citizens,often known as volunteered geographic information,has recently provided an interesting alternative to traditional authoritative information from mapping agencies and corporations,and several recent papers have provided the beginnings of a literature on the more fundamental issues raised by this new source.Data quality is a major concern,since volunteered information is asserted and carries none of the assurances that lead to trust in officially created data.During emergencies time is the essence,and the risks associated with volunteered information are often outweighed by the benefits of its use.An example is discussed using the four wildfires that impacted the Santa Barbara area in 20072009,and lessons are drawn.