Any low-cost hand-held GPS can be used in this type of projects. The geographic location (Latitude, Longitude, and Elevation) for each point is recorded using Topcon GMS-2 receiver. The GMS-2 receiver is a single-frequency, GPS receiver and hand-held controller built to be compact and portable receiver for the GIS surveying market [10]. According to Nisanci [11], GMS-2 receiver provides the functionality, accuracy, availability, and integrity needed for fast and easy data collection. However, the GPS has some restrictions and the choice of each point is selected such that the equipment is exposed to various error sources. For example, GPS signals may be reflected from the neighboring water strip and the angle of clearance to satellites is obstructed by the tree canopy. In addition, the inconsistent GPS readings may be caused by signal multipath from nearby buildings and/or bad satellite geometry, which reduce the accuracy.