Research On Key Technology Of 3D Urban Planning Aided System

The advancement of computer software and hardware technology promotes the development of three-dimensional technology.Geographic Information Systems(GIS),as one of the core technologies of "Digital City",has also entered the era of "dimension upgrading".Three-dimensional GIS(3DGIS),combined with various services and applications,penetrates into many industries and plays an increasingly important role.By visually displaying the planning scheme and assisting the planning managers to examine and approve various planning schemes through 3D spatial analysis method,it provides a basis for scientific planning and cost saving.At present,the application of 3DGIS in assistant decision-making of urban planning mainly solves the following requirements: first,the unified management and display of massive 3D model data.Secondly,the spatial analysis ability of GIS is used to calculate relevant indicators,such as visual range,sunshine duration,color ratio of building facade,etc.In order to provide assistant decision support for urban planning related business.Firstly,this paper introduces the research status of organization and loading of massive 3D data and 3D spatial analysis methods at home and abroad,and summarizes the characteristics of the mainstream three-dimensional GIS software platform around the world.Aiming at the bottleneck of restricting rendering and displaying efficiency of 3D city model,this paper explores the key technology of visualization of massive three-dimensional city model,and optimizes and improves some specific spatial analysis functions of assistant decision-making.This paper mainly studies two parts: data organization and scheduling of 3D model and 3D spatial analysis algorithm for urban planning.To solve the problem of low rendering efficiency of 3D city model with large amount of data,edge collapse algorithm based on quadratic error measure is used to simplify the model data.Levels of Detail(LOD)is constructed according to different levels of simplification,and memory dynamic scheduling is realized by paging database technology pre-reading cache LOD(PageLOD).A 3D city model with large amount of data is realized fluent display.In the aspect of 3D spatial analysis algorithm,the calculation and display of view analysis,sunshine analysis and skyline analysis in real 3D scene are mainly studied.Finally,based on the key technologies,the urban planning three-dimensional decision-making system is designed and implemented.