# Detection and Monitoring of Topography Changes at the Tottori Sand Dune Using UAV-LiDAR

## TL;DR

A UAV-LiDAR system with GNSS and GCPs was used to monitor centimeter-level changes in Japan's Tottori Sand Dunes, revealing up to 0.4 m elevation shifts from wind-driven sand movement.

## Contribution

An integrated UAV-LiDAR system with optimized GCPs achieves centimeter-level accuracy for monitoring coastal dune topography.

## Key findings

- Digital elevation models (DEMs) from LiDAR point clouds achieved centimeter-level accuracy.
- Wind-driven sand transport caused elevation changes of up to 0.4 m in the Tottori Sand Dunes.

## Abstract

What are the main findings?
An integrated UAV-LiDAR sensor system with GNSS-RT and optimized ground control point (GCP) design enables centimeter-level digital elevation models (DEMs) from LiDAR point clouds, which are validated against GNSS reference data.Subtle dune dynamics, including elevation changes of up to 0.4 m associated with wind-driven sand transport, were detected.

An integrated UAV-LiDAR sensor system with GNSS-RT and optimized ground control point (GCP) design enables centimeter-level digital elevation models (DEMs) from LiDAR point clouds, which are validated against GNSS reference data.

Subtle dune dynamics, including elevation changes of up to 0.4 m associated with wind-driven sand transport, were detected.

What are the implications of the main findings?
This study demonstrates UAV-LiDAR as a robust environmental sensing framework for coastal dune conservation and hazard assessment.

This study demonstrates UAV-LiDAR as a robust environmental sensing framework for coastal dune conservation and hazard assessment.

Coastal sand dunes, shaped by aeolian and marine processes, are critical to natural ecosystems and human societies, making their morphological monitoring essential for effective conservation. However, large-scale, high-precision monitoring of topographic change remains a persistent challenge, a challenge that advanced sensing technologies can address. In this study, we propose an integrated, sensor-based approach using a UAV-mounted light detection and ranging (LiDAR) system, combined with a GNSS-RTK positioning unit and a novel ground control point (GCP) design to acquire high-resolution topographic data. Field surveys were conducted at four time points between October 2022 and February 2023 in the Tottori Sand Dunes, Japan. The digital elevation models (DEMs) derived from LiDAR point clouds achieved centimeter-level accuracy, enabling reliable detection of subtle topographic changes. Analysis of DEM differencing revealed that wind-driven sand deposition and erosion resulted in elevation changes of up to 0.4 m. These results validate the efficacy of the UAV-LiDAR sensor system for high-resolution, multitemporal monitoring of coastal sand dunes, highlighting its potential to advance the development of environmental sensing frameworks and support data-driven conservation strategies.