Research On Railway Engineering Geology Survey System Based On Google Earth

Abstract:Railway engineering geology survey is an important work that affects the overall railway design. When railway technological conditions and trends are initially determined, geological conditions of railway engineering become one of the decisive factors that influence line position, bridge, subgrade, tunnel and station. At the beginning of the railway engineering geology survey, shortage of field data and old age of geological data lead to a situation that efficiency and quality of the railway engineering geology survey are difficult to meet the needs of the project. The emergence of Google Earth3D geographic information platform provides a better way to resolve the above problems. Therefore, method based on Google Earth for the railway engineering geology survey is put forward and a detailed study on the Google Earth application in railway engineering geology survey is made in this paper. The main research contents are as follows:1) Railway engineering geological remote sensing method based on Google Earth is proposed in this paper.The interpretation and identification of geomorphic partition, geological boundary and geological structure, unfavorable geology on the Google Earth are realized through establishments of the railway engineering geology survey data model, mouse pick-up mechanism, data storage management mechanism and use of remote sensing information extraction method.2) Based on coordinate transformation principle, technologies such as ObjectARX, KML and C#are adopted, and linkage interaction between multiple windows based on Google Earth is realized in this paper. An exchange of data between Google Earth and Auto CAD platforms is completed and a seamless connection and synchronous display of system data and external reconnaissance data are realized.3) Railway engineering geological spatial analysis method based on Google Earth is proposed. Through setting up pick-up mechanism on Google Earth platform and using the basic geometry principle, measurement of interpretation results’coordinate, length, area is realized in this paper. Besides, overlaying of topographic and geographic map and line investigation on Google Earth platform are also realized. Based on Google Earth, strata attitude and true thickness measurement method which use gauss projection transformation, the least squares principle, plane fitting, and KML is proposed, and3D visualization display of strata attitude and true thickness is realized.4) Railway engineering geology survey results’3D visualization display based on Google Earth is realized. Based on Google Earth multi-source geographic information and use of engineering data, the efficient organization and management methods and KML dynamic loading technology,3D path roaming, survey results and route plan comprehensive display are realized, which provide important basis for railway engineering geology reconnaissance, line selection, project decision-making and review.5) By using the above theory and method and integrating applications of the Google Earth COM API, ObjectARX, C#, C++, KML, ACCESS database interface or development technology, railway engineering geology reconnaissance system based on Google Earth (GERIS) are developed. System is already applied in geological reconnaissance of railways such as Shiyi railway and Xiangpu railway. Practice has proved that, the theory and method mentioned in this paper are practical to deal with the problem of railway engineering geological survey and can satisfy the engineering needs.