Estimation of Soil Volumetric Erosion Using GPS and Unmanned Aerial Vehicle: A Case Study at Universiti Teknologi Malaysia, Johor

Abstract

In modern times, Global Positioning System (GPS) and Unmanned Aerial Vehicle (UAV) are widely used in surveying. Both types of equipment can be used in volume determination. The calculation of land volume is one of the essential engineering works (i.e., construction sites, quarries/mines, landfills) that rely on the topographic survey. The UAV and GPS are two contemporary survey techniques for acquiring topographic data and later for soil volume estimation. This research aims to compare GPS and UAV aerial photos to estimate the soil eroded volume. The study area of this project is Persiaran Satelit, Universiti Teknologi Malaysia (UTM), where the data collection was conducted using GPS Real-Time Kinematic (RTK) and UAV photogrammetry. The GPS RTK technique is utilised to conduct a topographic survey, while UAV photogrammetry, on the other hand, performs an aerial photo survey. A GPS static technique of two hours of observation is performed to estimate more reliable referenced coordinates to be used as the ground control points (GCPs) for the aerial photos. This project utilises AutoCAD Civil 3D and Pix4D Mapper to analyse the data for GPS and UAV, respectively. Both methods show different results in land volume up to 2.59% due to the different densities of spatial data and survey points interpolation. In addition, the Digital Elevation Model (DEM) and analysis of soil erosion in this study have demonstrated the total volume loss throughout the six months of study is 0.55% and 1.47% for GPS-RTK and UAV, respectively. Hence, this study concludes that soil volume estimation using UAV photogrammetry and GPS RTK method is feasible in soil erosion monitoring.