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Liu C.,Tongji University | Liu C.,Key Laboratory of Advanced Engineering Surveying of State Bureau of Surveying and Mapping | Yang C.,Tongji University | Fan Y.,Tongji University
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/ Geomatics and Information Science of Wuhan University | Year: 2010

Instantaneous traffic information can be collected by the Floating Car Data (FCD) method. Based on the establishment of ″Shenzhen Urban Transportation Simulation System″ (SUTSS), the paper explored how to use taxis as the data collection sensors in Shenzhen. Due to the nature of FCD, continuous GPS data such as routing velocities and coordinates can be collected by any GPS equipped vehicle. Therefore, relevant algorithms are developed and utilized for the map-matching according to probability and statistical theories. Furthermore, road segment velocity matching methods based on the Metropolis criteria is extended and relevant validation is carried out through the comparison of estimated and measured results. The major objective of this method is to obtain more accurate road segment travel time through the combination those estimated by FCD and historical ones. This can significantly improve the reliability of instantaneous traffic information before its web publication. Finally, this paper introduces the architecture and the realization of a web Geographical Information System (GIS) and FCD-based instantaneous traffic information dissemination system for the whole of Shenzhen City. Source


Yao L.B.,Tongji University | Yao L.B.,Key Laboratory of Advanced Engineering Surveying of State Bureau of Surveying and Mapping | Sun H.L.,Tongji University | Zhu L.X.,Tongji University | Zhou Y.Y.,Tongji University
Survey Review | Year: 2014

Under the background of the landslide deformation monitoring of the left mountainside at Fuchunjiang Dam, we developed an automatic Landslide Deformation Monitoring System (LDMS) based on the TCA2003 surveying robot. Our LDMS extended the applications of TCA2003 in deformation monitoring by using GEOCOM serial-port functions. The system has the following features: automatic multiple observation sets measuring, automatic field data sheets generating, hydrograph plotting and deformation analysing. The new system had been developed and implemented under the environment of Visual Czz 6.0. The system has simpler operations and stronger practical applicability, compared with previous landslide deformation monitor methods. Based on analysis of the coordinates of Leftpt point on the sliding mass of left mountainside on Fuchunjiang Dam, displacement occurred in recent years, the whole monitoring of the sliding mass is essential. The analysis of the data achieved by LDMS showed that the sliding mass had no clear uniform deformation, and each part of the sliding mass was noticeably different in the slipping speed in the landslide direction. Hence, regular monitoring is essential to prevent the sliding mass from local landslides. © 2014 Survey Review Ltd. Source

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