Study On Spatial Data Model Of Urban Drainage Topology

The urban drainage system is one of the most important municipal engineering facilities.In recent years,as the indispensable content of smart city,the construction of intelligent network has risen to national strategic height.Intelligent urban drainage system,not only can realize the digital management of existing facilities,but also need to provide drainage and water-logging simulation analysis,real-time monitoring and other functions,which requires the system based on the city class,or even city-group class of the pipe network data to perform accurate and efficient spatial topology analysis.The choice of the drainage topological spatial data model reflects the level of expression of the topology characteristics and is directly related to the accuracy and efficiency of the spatial topology analysis.The current drainage system topology analysis is mainly based on two kinds of structures,one is suitable for small-scale pipe network's planning.The efficiency of this model is higher,but for the city-class pipe network data,the model shows a very low storage efficiency and high difficulty in building.The other is attribute-based topology structure.It is based on the database,which can be used to deal with a large amount of data efficiently.It is widely used in the urban pipe network management platform,but there are limitations to the support of the spatial topological analysis.First,the expression of topological features is not sufficient,so that the arithmetic logic has much room for optimization;furthermore,the physical mechanism resulted in the topology analysis of complex operational efficiency is not very good,which will become the bottleneck of city-group's big data analysis in the future.The purpose of this paper is to solve the problem of topological expression and analysis efficiency of urban drainage topology in theory,and to provide a solution for achieving the efficient spatial analysis of massive data of urban drainage system,and to provide a more powerful support for drainage and water-logging decision in the background of large data.This paper carries out the research based on the project named Urban Drainage GIS System Construction Technology Research".The model combines the drainage engineering with the geological characteristics.On the one hand,it improves the description of topological relations on the logical level;on the other hand,it improves the computational efficiency on the physical level.The main research results are as follows:(1)Drainage Topological Spatial Data Model for Pipeline NetworkIn this paper,the object-oriented method unfolds from four aspects:conceptual model,logical model,physical model of topology storage and topology creation.At the level of concept and logic,this paper conducts a more detailed abstraction of drainage topological relationships and objects,and develops topology rules.At the level of physical storage,this paper develops logical model as well as the corresponding topological storage method,and develops the algorithms for dynamic change of topology.(2)The Method of Indexing the Pipeline Composite Structure Based on the Improved Orthogonal ListIn order to avoid the problems of prolonged response time and inefficient when massive data are approached,this paper proposes a method of indexing the pipeline composite structure based on the improved orthogonal list.The pipeline composite structure is used as the basic object of index,improves the productive structure of the orthogonal list at the same time,which makes it associate with the R+index,improve the efficiency of data access pipeline analysis,provide the technical basis for the efficient real-time topology of massive data.(3)Model Application and ExperimentThe above results are applied to the geographical information system of Zhenjiang drainage network GIS system,and the effectiveness and efficiency of the model are verified through the system.Experiments show that the validity of the model is correct,and the model has higher data access efficiency under the condition of large amount of data.The data shows that the traditional model and the model in this paper are different less in the range of the smaller area of the pipe network.The traditional model acts even slightly better than the model in this paper.But with the increase of the pipe network area,the efficiency of the model in this paper shows a great advantage,such as,when the pipe network area is 12.59km2,the access efficiency of the model in this paper is about 3 times of that of the traditional model.