Research On Spatio-Temporal Object Model Construction And 3D Visualization Of Contaminated Sites

In recent years,with the reform of social and economic system,the process of urbanization has been accelerated,and soil environment management has become an important issue in China’s urban construction,planning and development.With the construction of China’s chemical industrial parks,a large number of chemical enterprises are facing the situation of relocation or shutdown,and the resulting pollution of a large number of legacy sites within the city needs to be solved urgently.The current research on contaminated sites mainly focuses on soil contamination evaluation and health risk assessment,and the main presentation of its data is mostly in the form of flat effects,which is difficult to express and display the entity information in contaminated sites in multiple dimensions.Taking a steel plant in Chongqing as an example,this paper constructs a three-dimensional spatio-temporal object of the contaminated site and relies on the idea of multi-grained spatio-temporal object to describe and express the spatio-temporal object characteristics completely,so as to realize the integration and fusion of the contaminated site information.Relying on the demonstration site of the national key R&D program project,the research application system is developed to verify the feasibility and practicality of the research method in this paper.The main research work of this paper is as follows:(1)Raw data processing of contaminated sites.The relevant concepts of contaminated sites are described and the industry characteristics are analyzed.For the problems of large volume,data redundancy and low utilization efficiency of the original contaminated site data,this paper adopts the processing method of manual combined with Chinese word separation to extract the attribute information from the site files,and this method can extract the entity attribute information of the site efficiently.In addition,the problematic data in the subsequent model construction process are sorted out,and the problems of missing values,abnormal values and non-uniform coordinate system are taken as examples.A relatively efficient method was used for processing,and data storage was carried out with the help of corresponding database tools.The original data processing of the contaminated site lays the foundation for the construction of the model and the efficient representation of the 3D model.(2)The design of spatio-temporal object model of contaminated sites and the study of feature description methods.According to the research theory of spatio-temporal objects,the real-world physical objects of contaminated sites are classified by using geographic cognition and combining the data features of contaminated sites,and on this basis,the above-ground space,underground space and integrated spatio-temporal object data models of contaminated sites are designed respectively,and according to the idea of multi-grain spatio-temporal objects,the basic feature terms and expanded feature terms description methods are designed to describe and express the spatio-temporal objects of contaminated sites.Based on the idea of multi-grained spatio-temporal objects,we design the basic feature term and extended feature term description methods to describe and express the spatio-temporal objects of contaminated sites,and complete the organization process of spatio-temporal object data of contaminated sites with spatio-temporal object features.(3)The actual model construction process and visualization study of spatio-temporal objects.Based on the data processing and object model design,specific models are constructed for the building class,borehole class,pollutant class,geological class and other infrastructure class models in the contaminated site,and the expanded description item templates of spatio-temporal objects are visualized by node-link method and tree diagram method respectively,which can better describe the connection between entities.Meanwhile,with the help of data model format conversion method and corresponding rendering scheme,a 3D digital platform is used to build a 3D visualization system of contaminated site environment to realize the 3D representation of spatio-temporal object models of contaminated sites,which is practically applied to the research of this paper.