Research On 3D Visualization Method Of Multi-scale Air Pollution Transport

Air pollution transport refers to the gradual diffusion process of pollutants in the atmosphere under the influence of meteorological factors.With visualizing pollutants that are invisible to the human eye in the atmosphere.It’s easy to see the changing law of air pollution concentration under the influence of meteorological factors,and show the severity of air pollution vividly.In addition to deepening people’s understanding of the environment,it enables decision makers to discover the temporal,spatial distribution and transportation rules of air pollution quickly,and make decisions in time.With the continuous development of monitoring technology,there are rich data types and large amount of data.Traditional air pollution visualization software has the problems of single data display,slow loading speed and poor visualization effect,which is difficult to meet the needs of complex visualization.In order to solve the above problems,the three-dimensional visualization method of multi-scale air pollution transport is studied in this thesis.Firstly,a multi-scale data organization model is designed.According to the characteristics of multi-type,multi-source,multi-scale and large amount of data,a multi-scale composite pyramid model which can organize and manage various types of data is proposed.In order to speed up data retrieval,B+3DOHR tree index is constructed.Secondly,this paper proposed a cache replacement strategy MCPCR based on compound pyramid model by researching data scheduling strategies.MCPCR can support the caching of multiple types of data effectively.In order to improve the cache hit rate and the user response speed,the spatial characteristics of data,user operation habits and the introduction of protection mechanism are considered comprehensively.Finally,the visualization of air pollution transport is studied.A hybrid rendering of air pollution visualization and wind field visualization is carried out by using Dual Deepth Peeling.The air pollution visualization is presented by direct volume rendering,the transparency of transfer function in volume rendering is designed based on the gradient characteristics,and the color mapping of transfer function is designed according to the air quality index classification.The visualization of wind field adopts the presentation of three-dimensional arrows in the point icon method and is processed by LOD resampling based on viewpoint to solve the problem of overlapping three-dimensional arrows.On the basis of the above content,a multi-scale three-dimensional visualization platform of air pollution transport is designed and realized.The visualization of air pollution transport is demonstrated at three scales of global,regional and city,and is compared with several commonly used visualization software.Multi-scale air pollution transmission 3D visualization platform can effectively display multi-dimensional air pollution information,Dynamic 3D visualization of multi-source data is carried out,and air quality management decisions can be supported.The system has good application value.