Impact of Varying Ground Control Points Configurations on the Accuracy of Unmanned Aerial Vehicle-Based Digital Elevation Models

Abstract

Ensuring the vertical and horizontal accuracy of UAV-DEM is crucial for precision of results in any geohazard modeling like flood modeling. Various factors affecting UAV-DEMs accuracy, particularly the number and spatial distribution of Ground Control Points (GCPs) used in the surveyed area. This study aimed to identify the most effective GCP configuration for the UAV-DEM by assessing its impact on the vertical and horizontal accuracy of UAV-DEMs, considering GCP configurations involving different numbers (4, 8, 12, 16, and 20) and distributions (Outer, Center, and Stratified). The investigation employed a Factorial Experimental Design with three replications. The results revealed that UAV-DEMs with 8, 12, 16, and 20 GCPs exhibited higher vertical accuracy compared to those with 4 GCPs. While 4, 8, 12 and 16 number of GCPs will have the same effect on the horizontal accuracy. Additionally, both outer and stratified distributions surpassed center distribution for both vertical and horizontal accuracy. Furthermore, the study produced 20-cm Vertical Accuracy Class with 10-cm Horizontal Accuracy class based on ASPRS Positional Accuracy Standards for Digital Geospatial Data of 2023. Consequently, the study recommends an optimal GCP configuration involving 8 GCPs with either Outer or Stratified Distribution for every 100-hectare (1 km²) study area.