Afterthe construction of subway main structure, in order to realize route adjustmentof alignment and gradient, it needs to survey the cross-section of subwaytunnel. Compared with conventional measuring methods, 3D laser scanning has thecharacteristics of non-contact measurement and can collect space 3D point clouddata with high density, this can improve the working efficiency for the subwaycross-section surveying. Based on the Leica Scanstation 2 scanners this paperanalyzed the 3D laser scanning point cloud data collection procedures and dataprocessing, expounded the subway cross-section surveying method based on pointcloud data; analyzed the feasibility of 3D laser scanning technology in theapplication of tunnel cross-section surveying based on the field validationdata. The results show that the cross-section measured by this method can meetthe technical requirements of route adjustment of alignment and gradient.
3D laser scanning technology can fast, efficient and accurate access high-precision measurement of the target point cloud data and provides the necessary conditions for the development of digital measuring. This paper gives an example of Subway and elaborates the method of 3D point cloud data acquisition, data processing and modeling, and verifies the feasibility of 3D visualization of Subway based on 3D laser.
The common point coordinate precision affect accuracy of coordinate transformation. In order to overcome the individual common point coordinate precision is too low or the error is large under some condition, a new method of high-precision coordinate transformation based on bursa model was discussed, which used the theory of robust resistance estimation to solve and calculate the high-precision coordinate transformation parameters, finally achieved the purpose of high-precision coordinate transformation. By calculation and comparison with experimental date, the result show that the method is practical and effective, so it is completely feasible in application surveying engineering.
Grid dependent tasks rescheduling problem currently are facing triggering frequent. Aiming at this problem, this paper introduces a simple based on Fault Index Based Rescheduling (FIBR). Then it put forward the improved method based on the tax mechanism successful index rescheduling method. Through the method, the grid system can accord the successful index value for task allocation relatively stable resources. At the same time, the method can make the most of the available resources are fully utilized, greatly reducing resource load imbalance situation, effectively improves the utilization of resources in history current stability judgment accuracy. The possibility of rescheduling trigger is reduced.
The set up of Web-based Surveying and Mapping data processing center, not only conducive to the standardization and modularity of Surveying and Mapping data processing, but also help the management and use of data, making the data providers and users no longer subject to geographic areas restrictions; at the same time as using the B/S (Browser/Server) architecture network platform, users avoid the installation process, saving the user's system resources.
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