GPS is one of the most practice data collection methods. As a result of removing of the selective availability (SA) error in 2000, accuracy of the absolute location determination is sub 10 meters in GPS (Mintsis,2002). In addition,it is about ± 3 meters while using the WAAS and EGNOS systems now (Hunter, 2002). It is possible to get the accuracy about ± 50 centimetres in case of using the DGPS method (Trimble, 2004).