COMPARING THE ACCURACY OF GOOGLE EARTH AND GLOBAL NAVIGATION SATELLITE SYSTEM’S (HI-TARGET GPS) IN TOPOGRAPHIC MAPPING

Abstract

Google Earth provides freely accessible spatial data, making it attractive for quick and preliminary mapping. However, topographic and engineering projects require highly accurate coordinates to ensure proper design and accurate material costing. Therefore, this study investigates the accuracy of Google Earth in comparison with GNSS. The aim of the study is to compare the positional accuracy of Google Earth and GNSS in topographic mapping. The study was conducted at the Nigerian Army University Biu temporary site. GNSS coordinates were obtained using a Hi-target GPS receiver, while Google Earth data were sourced online through GPS Visualizer. Civil CAD 3D and ArcGIS Pro were used to generate the Digital Elevation Model (DEM), Triangulated Irregular Network (TIN), and contour maps for both datasets, while Excel was employed for statistical analysis. The results showed that the GNSS system was far more accurate for geodetic, engineering, and plane surveying, whereas Google Earth was suitable mainly for reconnaissance or small-scale surveys. A correlation coefficient of 0.701 was obtained between both datasets, with a mean height difference of 5.47 m and a standard deviation of 1.42 m. The study concludes that GNSS should be adopted where high accuracy is essential particularly in construction design, execution, and material quantification because it provides more reliable and up-to-date spatial data than Google Earth, which exhibited higher misclosures.