Research Of Real-time Traffic Flow Data Displaying System Based On Qt/E

In recent years, researchers have established the Intelligent Transport System (ITS) with the combination of information technology, electronic technology, sensor technology, control technology, computer technology and many other subjects through their tireless efforts, which makes it easy to realize modern and scientific management of the entire transportation system. The public could obtain the real-time traffic flow data through ITS so that it is helpful for alleviating traffic congestion and reducing increasingly acute traffic pressure. Due to the update time of the existing ITS is too long and the real-time performance of the existing ITS is so poor, the public often need to choose their travel routes only relying on experiences. In this paper, a system is researched which could provide real-time traffic flow data to the public, so that they could choose their travel routes quickly and accurately. Works and results of this research were as follows:1. Based on the embedded Linux system, a real-time traffic flow data providing system was proposed, which is constructed by data processing center, vehicle-terminal, and wireless communication network. First of all, effective positioning data (including latitude, longitude, speed and azimuth, etc.) was collected by the GPS module of the vehicle terminal. Secondly, the collected information would be send to the data processing center through wireless communication network. Thirdly, the traffic flow data (including the average speed and the average traffic flow, etc.) were worked out based on the information of positioning on each vehicle and the relevant mathematical model. Finally, the traffic flow data would be send to the vehicle-mounted terminal for displaying through the wireless communication network.2. The technique of displaying digital map on the vehicle terminal was well studied. Firstly, the electronic vector map files around Yunnan University campus was converted into MapInfo table file under WGS1984geodetic coordinates and be stored into the Nand FLASH Memory. Secondly, detailed information of each map layer was fetched by using Mitab C++library. In the end, the electronic map was completely displayed on Qt/E graphical frame. Different from other systems’ dependence on the network, the digital map could be displayed very fast, that is, the system has the characteristics of strong real-time.3. The vehicle-terminals have very high accuracy on displaying real-time traffic flow data. The average speed of vehicles and average flow rate ware used to measure the traffic flows, and different colors (red, blue, yellow, green) would be displayed on the LCD to represent traffic condition. Further more, by the man-machine interactive functions in the program, the user could receive live traffic flow data according to their own preferences.