The Global Positioning System (GPS) is a satellite-based navigation system that can be used to find your location quickly anywhere in the world. The determined location findings can be called as GPS trajectory data set and it could be displayed over a digital map, which is known as map matching. However, since the inaccuracy exist in GPS trajectory data set, it is not possible to display the data properly over a digital map. In this case, the positions may be seen to be outliers. To avoid this problem, it is necessary to analyze the received GPS trajectory data set and process them before map matching.