Events The 6th International Electronic Conference on Remote Sensing

Event submissions

Published

This submission belongs to the session S5. Remote Sensing in Urban Areas of the event The 6th International Electronic Conference on Remote Sensing

Published date

14 Oct, 2026

Academic Editor

Riccardo Buccolieri

Citation

Kehinde Hassan Babalola, Kevin Musungu, Moluko Desmond Radamba, Olayemi Basirat Bello-Nonjengele, Comparison Between Unmanned Aerial Vehicle (UAV) and RTK-GNSS Surveying Methods for DEM Generation in Wetlands, in Proceedings of The 6th International Electronic Conference on Remote Sensing, 19 October–21 October 2026, MDPI: Basel, Switzerland

Facebook

Twitter

$Comparison Between Unmanned Aerial Vehicle (UAV) and RTK-GNSS Surveying Methods for DEM Generation in Wetlands$

Kehinde Hassan Babalola ¹

Kevin Musungu ¹

Moluko Desmond Radamba ¹

Olayemi Basirat Bello-Nonjengele ¹

1. Civil Engineering and Geomatics, Faculty of Engineering and the Built Environment, Cape Peninsula University of Technology, Cape Town 7536, South Africa

Abstract

Advancements in unmanned aerial vehicle (UAV) technology have improved remote sensing and photogrammetry, enabling high-resolution terrain mapping. This study evaluated the accuracy of Digital Terrain Models (DTMs) derived from UAV-based structure-from-motion (SfM) photogrammetry by comparing them with DTMs derived from real-time kinematic global navigation satellite system (RTK GNSS) survey data in the Steenbras Lower Dam wetland catchment, Cape Town, South Africa. High-resolution RGB imagery was captured using a DJI Phantom 3 UAV at an altitude of 35 m above the highest terrain point. Four ground control points were established using post-processed GNSS observations, with the same GNSS survey used to acquire the terrain elevation data. Pix4D software was used to reconstruct the terrain and produce digital surface and terrain models, orthophotos, and ultra-high-resolution point clouds. We assessed accuracy by overlaying 1,502 sampling points on both DTMs. Tall vegetation along the wetland's northern and southern periphery affected initial metrics, leading to Cross-DTM elevation discrepancies of up to 0.5 m at the wetland's edges. After filtering out absolute differences exceeding 0.5 m, the median elevation difference decreased from 0.464 m to 0.222 m, the median difference reduced from 0.344 m to 0.217 m, and the RMSE dropped from 0.605 m to 0.260 m. These results show that UAV-derived DTMs provide reliable, precise topographic information for wetland catchment mapping.

Keywords

UAV/GNSS-RTK

precision/accuracy

assessment

sustainable approach

ground control point

Digital Elevation Model.

ObliqueFit: A MATLAB Tool for 2D Oblique Spatial Analysis Using LiDAR and Photogrammetric Point Clouds

Spatiotemporal Variability, Drivers and Extreme-Heat Response of Surface Urban Heat Islands Across Italian Cities