On-line Spatiotemporal Visualization System For Trajectory Emissions

At present,the vehicle exhaust emissions have become one of the main sources of pollution in China's urban atmosphere.It is necessary to provide data support for the protection and management of the environment and to transform the economic strategy of the macro-control economy by analyzing the time and space distribution of the vehicle exhaust emission,reasonably planning the traffic network,adjusting the traffic flow,reducing or avoiding the pollution caused by road congestion And planning to provide a strong basis for decision-making.In addition,it is also convenient for urban residents to travel planning,to avoid a serious period of exhaust pollution and traffic sections.Therefore,it is important to analyze the impact of vehicle exhaust emissions on the urban traffic environment.In this paper,we first study the exhaust emission factor of the Comprehensive Modal Emission Model(CMEM)to calculate the trajectory data and draw the calculation method of the comprehensive index of the environmental quality.Secondly,this paper also studies the storage management method of massive trajectory data.Aiming at the characteristics of unstructured storage model and its corresponding database products,a trajectory data storage management method based on unstructured storage model is proposed,which includes data organization mode of trajectory data in unstructured storage model database,dotted line storage conversion method and The union of data sets.Then,based on the data that has been stored and managed,the key technologies of Web visualization of vehicle trajectories and their exhaust are studied,including Web service framework based on Node.js,online visual analysis of visualization and trajectory 3D visualization technology.On this basis,the time and space visualization system of vehicle exhaust emission with Wuhan taxi data as an example is designed and implemented.Finally,this paper evaluates the functions of the vehicle trajectory and its on-line visualization analysis system,and analyzes the microscopic cycle of air and space and the macro-exhaust space-time model.Microscopic found that some taxi drivers tend to go to the airport passengers,and the number of round trips back and forth a lot of regular and regular.Also found that bicycles at the intersection,business district,Hou Hu Avenue,the exhaust emission concentration is larger,indicating that the cycling movement in these locations more likely to discharge more exhaust,which is consistent with the actual situation.Macroscopically,the timing of the distribution of exhaust gas is very obvious.Around 8 am and around 7 pm,with more taxi activities,there are more exhaust emissions and more serious traffic pollution.It's suggested that going out activities such as going biking should be avoidedduring this period of time.It's also found that Hongshan District was the largest emissions district of taxi emissions,in thatHongshan occupies a large proportion of the whole test area.According to the analysis of the road statistics on taxi exhaust emissions during different time distribution,we found that Wuhan,the longest main road Jiefang Avenue often ranked the forefront.These results show that the taxi pollution of the system is consistent with the realityof the road condition,which proves the rationality of the functional application of the system.The result of visual analysis obtained from the system can support decisions make and make up the current defectof the Online application of vehicle exhaust emission visualization system,which can provide important reference value for urban traffic environment management and public travel planning.