Research On Railway Location Design Based On The Data Source From Google Earth

The traffic network has to perform at present in our country, railway construction has avery important significance as the indispensable component, so it will be always in the rapiddevelopment of the state for quite some time. Because of this it placing greater demands forthe work of prospecting and design. Google Earth is an digital earth software developed byGoogle Company, integrating the information of satellite images、aerial photos、3D terrainmodels, whose data structure meets the requirement, and especially it helps a lot for obtainingtopographic data at the pre-feasibility stage of railway construction as it is an open and gratissoftware, accordingly it Has the important practical significance to introducing Google Earthto the prospecting and design work.This thesis carries on the analysis of the data sources and software Features firstly,combining research and application at home and abroad, puts forward taking the Google Earthas a design platform for digitalize route selection，mainly carry out research work for thefollowing aspects.⑴Extracting pile coordinate from Google Earth. Google Earth has two kinds ofsecondary development, including KML document and COM API. Google Earth use KMLdocument for data saving and conversion, by the use of writing KML document, brought theterrain model and geographic information to show, also could show the3d renditions by theuse of third-party software’s conversion function. Google Earth supplies developmentinterface of COM API, set up appropriate camera height, sampling point density, deflectionangle of view, movement of window, to realize the function of extraction of coordinate alongthe path,⑵Take comparison between downloading date and measured data in the area of routeselection, in order to ensure the measurement precision in conformity with specificationrequirement. Meanwhile it realize the conversion function between WGS-84coordinate inGoogle Earth and Gauss plane coordinate used for practical work by means of mathematicaltechnique, then verify the precision and reliability through the example.⑶On the basis of downloading date from Google Earth, it can determine the planar lineand build initial line of vertical section. Considering the specific requirements such as: leastslope length, maximum slope, maximum slope poor，altitude constraint and so on. Meanwhileconsider the position of bridge and tunnel, automatically design the line of vertical sectionwhich can meet the requirement. Then combined with the railway cross section design standard chart, design calculation program which can compute the sub-grade engineeringearthwork, actualize automatic calculation under different route scheme as the main basis forscheme comparison, and prove the correctness and reliability through the example.