Research On Location Method Of Line Spatial Structure Based On GIS

Railway line design has high level of dependence on surveying and mapping technology.The technology of automatic route selection based on GIS has been a hot research topic,which involves the direction determination of the line,the selection of the schemes,the geological route selection,the 3D virtual simulation and so on.However,the essence of railway route selection is to select the spatial location of the line and reasonably distribute the spatial structures such as subgrade,bridge,tunnel,culvert,station,etc.The decision level of line selection depends on the expertsmore.In order to realize the intelligent design of line selection,it is necessary to imitate the expert’s decision making idea,to learn and summarize from the existing cases,to realize the management of the existing cases,to analyze,to excavate and to learn again,so as to improve the intelligent process of line selection design.Attribute management of existing cases can be achieved effectively by using GIS.It is possible to simulate the expert decision making by making use of its powerful function of spatial analysis.The optimization of line space structure distribution line is an important link to realize intelligent decision.Combining with GIS’ powerful data management and analysis function,multi-attribute management model of existing case is designed.Using the theory of multi dimension spatial similarity to simulate the expert decision making,optimization method for the distribution of the line spatial structure is studied in this paper.It can provide some technical support for the line intelligent decision.To this end,the main contents of this paper are as follows:Based on the powerful data management and analysis function of GIS,this paper take advantage of file database and attribute selection tools to study the optimization method for distribution of line space structure.The main contents include the following aspects:(1)Engineering attribute partition and database design based on caseBased on collecting engineering cases,the main engineering attributes that affect the distribution of spatial structures(subgrade,bridge and tunnel)are obtained and the project attributes and unit price are collated in the Excel table.A file geographic database is created in the GIS,and then the Excel form is imported by using the function of importing data.The construction of the database is completed.(2)Similarity judgment method based on multidimensional engineering attributesWith the help of the data analysis and screening function of GIS,line space similarity algorithm based on multi attributes is proposed and the corresponding algorithm is set up in GIS.After application the highest similarity with the engineering casecan be found in the file database.(3)Automatic generation and application of engineering cost based on similarityThe highest similarity engineering case is seen as the base price.The differences of the engineering attributes are found out through the comparison of the proposed project and the project case.With the help of GIS data analysis,the screening function and the linear interpolation,coefficients of these differences impact on the price are got.By multiplying the base price and the coefficients,the estimated unit price of each line space structure in the proposed project will be obtained.(4)Spatial distribution method of linebased on GISTheoptimal total cost ofsubgrade,bridge and tunnel is taken as the objective function.Optimal distribution function of line structures is designed.An example is given to calculate the unit price of line structures in a part of a certain length of line.Different boundary heights of bridge,tunnel and subgrade are selected and the initial feasible result is obtained.The optimal distribution scheme is obtained by the method of multi combination cyclic iteration.