地面站导航电子地图是操作员用来监控无人驾驶装备的唯一平台,也是进行线路规划和自主决策的重要信息源。现有的导航电子地图一般存在价格昂贵、对高程数据支持不足以及依赖互联网等缺陷。本文提出了一种新的基于OpenStreetMap的地面站...地面站导航电子地图是操作员用来监控无人驾驶装备的唯一平台,也是进行线路规划和自主决策的重要信息源。现有的导航电子地图一般存在价格昂贵、对高程数据支持不足以及依赖互联网等缺陷。本文提出了一种新的基于OpenStreetMap的地面站导航电子地图实现方法。首先,利用原始OSM数据搭建地图瓦片服务后台;然后将90 m SRTM高程数据处理成地形阴影和地形颜色渐变栅格文件;针对每个栅格文件,在瓦片服务后台的样式配置文件中添加相应图层并定义其渲染格式;最后,在地面站软件中实现地图客户端模块,向瓦片服务后台请求瓦片,并显示在地面站界面上。利用该方法实现的地面站导航电子地图可以提供0~18个缩放级别的中国范围的数据,显示0~13个缩放级别的立体地形地貌,并且无需互联网支持。本文使用该方法实现了某型无人机的地面站导航电子地图模块,并成功应用该无人机仿真系统。展开更多
A land-use map at the regional scale is a heavy computation task yet is critical to most landowners,researchers,and decision-makers,enabling them to make informed decisions for varying objectives.There are two major d...A land-use map at the regional scale is a heavy computation task yet is critical to most landowners,researchers,and decision-makers,enabling them to make informed decisions for varying objectives.There are two major difficulties in generating land classification maps at the regional scale:the necessity of large data-sets of training points and the expensive computation cost in terms of both money and time.Volunteered Geographic Information opens a new era in mapping and visualizing the physical world by providing an open-access database valuable georeferenced information collected by volunteer citizens.As one of the most well-known VGI initiatives,OpenStreetMap(OSM),contributes not only to road network distribution information but also to the potential for using these data to justify and delineate land patterns.Whereas,most large-scale mapping approaches-including regional and national scales–confuse“land cover”and“land-use”,or build up the land-use database based on modeled land cover data-sets,in this study,we clearly distinguished and differentiated land-use from land cover.By focusing on our prime objective of mapping land-use and management practices,a robust regional land-use mapping approach was developed by integrating OSM data with the earth observation remote sensing imagery.Our novel approach incorporates a vital temporal component to large-scale land-use mapping while effectively eliminating the typically burdensome computation and time/money demands of such work.Furthermore,our novel approach in regional scale land-use mapping produced robust results in our study area:the overall internal accuracy of the classifier was 95.2%and the external accuracy of the classifier was measured at 74.8%.展开更多
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)plat...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.展开更多
OpenStreetMap(OSM)data are widely used but their reliability is still variable.Many contributors to OSM have not been trained in geography or surveying and consequently their contributions,including geometry and attri...OpenStreetMap(OSM)data are widely used but their reliability is still variable.Many contributors to OSM have not been trained in geography or surveying and consequently their contributions,including geometry and attribute data inserts,deletions,and updates,can be inaccurate,incomplete,inconsistent,or vague.There are some mechanisms and applications dedicated to discovering bugs and errors in OSM data.Such systems can remove errors through user-checks and applying predefined rules but they need an extra control process to check the real-world validity of suspected errors and bugs.This paper focuses on finding bugs and errors based on patterns and rules extracted from the tracking data of users.The underlying idea is that certain characteristics of user trajectories are directly linked to the type of feature.Using such rules,some sets of potential bugs and errors can be identified and stored for further investigations.展开更多
Nowadays,several research projects show interest in employing volunteered geographic information(VGI)to improve their systems through using up-to-date and detailed data.The European project CAP4Access is one of the su...Nowadays,several research projects show interest in employing volunteered geographic information(VGI)to improve their systems through using up-to-date and detailed data.The European project CAP4Access is one of the successful examples of such international-wide research projects that aims to improve the accessibility of people with restricted mobility using crowdsourced data.In this project,OpenStreetMap(OSM)is used to extend OpenRouteService,a well-known routing platform.However,a basic challenge that this project tackled was the incompleteness of OSM data with regards to certain information that is required for wheelchair accessibility(e.g.sidewalk information,kerb data,etc.).In this article,we present the results of initial assessment of sidewalk data in OSM at the beginning of the project as well as our approach in awareness raising and using tools for tagging accessibility data into OSM database for enriching the sidewalk data completeness.Several experiments have been carried out in different European cities,and discussion on the results of the experiments as well as the lessons learned are provided.The lessons learned provide recommendations that help in organizing better mapping party events in the future.We conclude by reporting on how and to what extent the OSM sidewalk data completeness in these study areas have benefited from the mapping parties by the end of the project.展开更多
以我国区域为研究对象,分析了OpenStreetMap土地覆被信息的时空特征。结果表明,该数据在我国东北、华北、西北、华中、东南和西南6个地理分区均呈聚集状态分布,且数量表现出明显的差异性,东南区域是土地覆被信息最为集中的区域,该区域...以我国区域为研究对象,分析了OpenStreetMap土地覆被信息的时空特征。结果表明,该数据在我国东北、华北、西北、华中、东南和西南6个地理分区均呈聚集状态分布,且数量表现出明显的差异性,东南区域是土地覆被信息最为集中的区域,该区域仅占研究区域总面积的5%,却集中了土地覆被信息总量的33%;土地覆被信息以人工地表和水体为主,二者之和约占土地覆被信息总量的80%,其次为林地、草地、耕地,裸地数量最小;随着空间分辨率从30 m升尺度至500 m,各种类别的样本数据均随之减少,但林地、草地及耕地的减少速度明显低于人工地表和水体;年际及月季尺度分析表明,除裸地外,其余5种土地覆被类别均呈现较为显著的增加趋势,这说明Open Street Map数据具有稳定的数据来源,具有较好的现势性,可以形成一定的时间序列。该研究为未来大尺度土地覆被遥感产品生产及验证过程中训练、参考数据的选择,特别是人工地表和水体,提供了一定参考,也为土地覆被遥感产品更新完善提供了有效的数据来源。展开更多
The number of people registering in an online community depends on two main factors:interest in,and awareness of,the project.Registering to a project does not,however,imply contributing to it,as lacking the knowledge ...The number of people registering in an online community depends on two main factors:interest in,and awareness of,the project.Registering to a project does not,however,imply contributing to it,as lacking the knowledge and skills can be a barrier to participation.In order to identify the nature of events that might have facilitated or hindered enrollments in the OpenStreetMap(OSM)project over time,we analyzed the correlations between the number of new participants and the events that dotted its history.Four different metrics were defined to characterize participants’behaviors:the daily number of registrations,the daily number of participants that made a first contribution,the delays between contributors’registration and their first edits,and a daily contribution ratio built from the number of new contributors and the number of new registered members.Time series analyses were used to identify trends,and outstanding variations of the number of participants.An inventory of events that took place along the OSM project’s history was created and appreciable variations of the metrics have been linked to events that seemed to be meaningful.Although a correlation does not imply causality,many of the explanations these correlations suggest are supported by the results of other studies,either directly or indirectly.For instance,when considering the time participants spend as“lurker”,as well as on the nature of the contribution of early participants.In other cases,they suggest new explanations for the origin of the spam accounts that affect registration statistics,or the decline in the proportion of registered members who actually become contributors.展开更多
The comprehension of folksonomies is of high importance when making sense of Volunteered Geographic Information(VGI),in particular in the case of OpenStreetMap(OSM).So far,only little research has been conducted to un...The comprehension of folksonomies is of high importance when making sense of Volunteered Geographic Information(VGI),in particular in the case of OpenStreetMap(OSM).So far,only little research has been conducted to understand the role and the evolution of folksonomies in VGI and OSM,which is despite the fact that without a comprehension of the folksonomies the thematic dimension of data can hardly be used.This article examines the history of the OSM folksonomy,with the aim to predict its future evolution.In particular,we explore how the documentation of the OSM folksonomy relates to its actual use in the data,and we investigate the historical and future scope and granularity of the folksonomy.Finally,a visualization technique is proposed to examine the folksonomy in more detail.展开更多
文摘地面站导航电子地图是操作员用来监控无人驾驶装备的唯一平台,也是进行线路规划和自主决策的重要信息源。现有的导航电子地图一般存在价格昂贵、对高程数据支持不足以及依赖互联网等缺陷。本文提出了一种新的基于OpenStreetMap的地面站导航电子地图实现方法。首先,利用原始OSM数据搭建地图瓦片服务后台;然后将90 m SRTM高程数据处理成地形阴影和地形颜色渐变栅格文件;针对每个栅格文件,在瓦片服务后台的样式配置文件中添加相应图层并定义其渲染格式;最后,在地面站软件中实现地图客户端模块,向瓦片服务后台请求瓦片,并显示在地面站界面上。利用该方法实现的地面站导航电子地图可以提供0~18个缩放级别的中国范围的数据,显示0~13个缩放级别的立体地形地貌,并且无需互联网支持。本文使用该方法实现了某型无人机的地面站导航电子地图模块,并成功应用该无人机仿真系统。
文摘A land-use map at the regional scale is a heavy computation task yet is critical to most landowners,researchers,and decision-makers,enabling them to make informed decisions for varying objectives.There are two major difficulties in generating land classification maps at the regional scale:the necessity of large data-sets of training points and the expensive computation cost in terms of both money and time.Volunteered Geographic Information opens a new era in mapping and visualizing the physical world by providing an open-access database valuable georeferenced information collected by volunteer citizens.As one of the most well-known VGI initiatives,OpenStreetMap(OSM),contributes not only to road network distribution information but also to the potential for using these data to justify and delineate land patterns.Whereas,most large-scale mapping approaches-including regional and national scales–confuse“land cover”and“land-use”,or build up the land-use database based on modeled land cover data-sets,in this study,we clearly distinguished and differentiated land-use from land cover.By focusing on our prime objective of mapping land-use and management practices,a robust regional land-use mapping approach was developed by integrating OSM data with the earth observation remote sensing imagery.Our novel approach incorporates a vital temporal component to large-scale land-use mapping while effectively eliminating the typically burdensome computation and time/money demands of such work.Furthermore,our novel approach in regional scale land-use mapping produced robust results in our study area:the overall internal accuracy of the classifier was 95.2%and the external accuracy of the classifier was measured at 74.8%.
文摘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.
基金This research was supported financially by EU FP7 Marie Curie Initial Training Network MULTI-POS(Multi-technology Positioning Professionals)[grant number 316528].
文摘OpenStreetMap(OSM)data are widely used but their reliability is still variable.Many contributors to OSM have not been trained in geography or surveying and consequently their contributions,including geometry and attribute data inserts,deletions,and updates,can be inaccurate,incomplete,inconsistent,or vague.There are some mechanisms and applications dedicated to discovering bugs and errors in OSM data.Such systems can remove errors through user-checks and applying predefined rules but they need an extra control process to check the real-world validity of suspected errors and bugs.This paper focuses on finding bugs and errors based on patterns and rules extracted from the tracking data of users.The underlying idea is that certain characteristics of user trajectories are directly linked to the type of feature.Using such rules,some sets of potential bugs and errors can be identified and stored for further investigations.
基金supported by the European Community’s Seventh Framework Programme[FP7/2007–2013],[Grant No 612096(CAP4Access)].
文摘Nowadays,several research projects show interest in employing volunteered geographic information(VGI)to improve their systems through using up-to-date and detailed data.The European project CAP4Access is one of the successful examples of such international-wide research projects that aims to improve the accessibility of people with restricted mobility using crowdsourced data.In this project,OpenStreetMap(OSM)is used to extend OpenRouteService,a well-known routing platform.However,a basic challenge that this project tackled was the incompleteness of OSM data with regards to certain information that is required for wheelchair accessibility(e.g.sidewalk information,kerb data,etc.).In this article,we present the results of initial assessment of sidewalk data in OSM at the beginning of the project as well as our approach in awareness raising and using tools for tagging accessibility data into OSM database for enriching the sidewalk data completeness.Several experiments have been carried out in different European cities,and discussion on the results of the experiments as well as the lessons learned are provided.The lessons learned provide recommendations that help in organizing better mapping party events in the future.We conclude by reporting on how and to what extent the OSM sidewalk data completeness in these study areas have benefited from the mapping parties by the end of the project.
文摘以我国区域为研究对象,分析了OpenStreetMap土地覆被信息的时空特征。结果表明,该数据在我国东北、华北、西北、华中、东南和西南6个地理分区均呈聚集状态分布,且数量表现出明显的差异性,东南区域是土地覆被信息最为集中的区域,该区域仅占研究区域总面积的5%,却集中了土地覆被信息总量的33%;土地覆被信息以人工地表和水体为主,二者之和约占土地覆被信息总量的80%,其次为林地、草地、耕地,裸地数量最小;随着空间分辨率从30 m升尺度至500 m,各种类别的样本数据均随之减少,但林地、草地及耕地的减少速度明显低于人工地表和水体;年际及月季尺度分析表明,除裸地外,其余5种土地覆被类别均呈现较为显著的增加趋势,这说明Open Street Map数据具有稳定的数据来源,具有较好的现势性,可以形成一定的时间序列。该研究为未来大尺度土地覆被遥感产品生产及验证过程中训练、参考数据的选择,特别是人工地表和水体,提供了一定参考,也为土地覆被遥感产品更新完善提供了有效的数据来源。
基金supported by a Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery GrantMemorial University of Newfoundland.
文摘The number of people registering in an online community depends on two main factors:interest in,and awareness of,the project.Registering to a project does not,however,imply contributing to it,as lacking the knowledge and skills can be a barrier to participation.In order to identify the nature of events that might have facilitated or hindered enrollments in the OpenStreetMap(OSM)project over time,we analyzed the correlations between the number of new participants and the events that dotted its history.Four different metrics were defined to characterize participants’behaviors:the daily number of registrations,the daily number of participants that made a first contribution,the delays between contributors’registration and their first edits,and a daily contribution ratio built from the number of new contributors and the number of new registered members.Time series analyses were used to identify trends,and outstanding variations of the number of participants.An inventory of events that took place along the OSM project’s history was created and appreciable variations of the metrics have been linked to events that seemed to be meaningful.Although a correlation does not imply causality,many of the explanations these correlations suggest are supported by the results of other studies,either directly or indirectly.For instance,when considering the time participants spend as“lurker”,as well as on the nature of the contribution of early participants.In other cases,they suggest new explanations for the origin of the spam accounts that affect registration statistics,or the decline in the proportion of registered members who actually become contributors.
基金partially supported by the Deutsche Forschungsgemeinschaft(DFG)project A framework for measuring the fitness for purpose of OpenStreetMap data based on intrinsic quality indicators[grant number FA 1189/3-1].
文摘The comprehension of folksonomies is of high importance when making sense of Volunteered Geographic Information(VGI),in particular in the case of OpenStreetMap(OSM).So far,only little research has been conducted to understand the role and the evolution of folksonomies in VGI and OSM,which is despite the fact that without a comprehension of the folksonomies the thematic dimension of data can hardly be used.This article examines the history of the OSM folksonomy,with the aim to predict its future evolution.In particular,we explore how the documentation of the OSM folksonomy relates to its actual use in the data,and we investigate the historical and future scope and granularity of the folksonomy.Finally,a visualization technique is proposed to examine the folksonomy in more detail.
