Investigatingurban-scalehumanmobilityusinglocationawaredevices.ppt

* * * * * * * * * * * * * * * Traffic density distribution It shows that top rank 20% streets account for 62.09% taxis traffic volume, and top 33.56% streets account for 80% taxis traffic volume. Vector field of the traffic flow Centrality Betweenness Straightness Plot of traffic density vs. betweenness Why low correlation? Population density estimated using phone call records Monte Carlo simulation result and betweenness High correlation between simulation result and betweenness --a natural result Next step: Considering distance decay Wrap up Location aware devices provide a convenient approach to modeling human mobility Each approach has its pros and cons Two levels of research Individual Metropolitan * * * * * * * * * * * * * * * * * * * * * * * * 北京大学 Geosoft实验室 Investigating urban-scale human mobility using location aware devices利用位置感知装置研究城市人口流动 王景丽 Human mobility Each individual moves in the geographical space. The trajectory轨迹 of one person is ad hoc特设的 Patterns can be found with a large amount of trajectories Such patterns are useful in many fields GIS needs to represent and model individual dynamics A trajectory of an individual in spatio-temporal space（时空空间） Applications Individual level个体层次 Social network research社会网络研究 Spatial spread of disease疾病的空间传播 Metropolitan level都市圈 Transportation planning交通规划 Land use planning土地利用规划 Location aware devices Mobile phones GPS receiver Individuals equipped with GPS receivers Taxis equipped with GPS receivers Individual trajectory extracted from phone call records One-day trajectory of a taxi with GPS the red lines denote the trajectories when there are passengers inside the taxicab; while the blue lines imply unoccupied statuses 红色线表示的轨迹，当有乘客在出租车；而蓝线意味着空闲状态。 Advantage and disadvantage 1 Mobile phones Advantage: Record the trajectories a huge number e.g. 100,000 of individuals during a relatively long period e.g. one year Disadvantage Precision精度, spatial and temporal Advantage and disadvantage 2 Taxies wi