Principles and practice of acquiring drone-based image data in marine environments

Abstract

With almost limitless applications across marine and freshwater environments, the number of people using, and wanting to use, remotely piloted aircraft systems (or drones) is increasing exponentially. However, successfully using drones for data collection and mapping is often preceded by hours of researching drone capabilities and functionality followed by numerous limited-success flights as users tailor their approach to data collection through trial and error. Working over water can be particularly complex and the published research using drones rarely documents the methodology and practical information in sufficient detail to allow others, with little remote pilot experience, to replicate them or to learn from their mistakes. This can be frustrating and expensive, particularly when working in remote locations where the window of access is small. The aim of this paper is to provide a practical guide to drone-based data acquisition considerations. We hope to minimise the amount of trial and error required to obtain high-quality, map-ready data by outlining the principles and practice of data collection using drones, particularly in marine and freshwater environments. Importantly, our recommendations are grounded in remote sensing and photogrammetry theory so that the data collected are appropriate for making measurements and conducting quantitative data analysis.

A Protocol for Aerial Survey in Coastal Areas Using UAS

“…These areas act as blind spots and affect the visibility of the benthic features and marine information. The sun angle and the UAV position during a flight are correlated as they affect the amount of sun glint in aerial images, the lighting of the benthic features and the shadows of the constructions on the shoreline [6,8,29]. As the sun angle gets bigger, the sun glint moves to the center of the image [21].…”

“…Thus, the calculation of the sun position at a study area is a critical parameter to the selection of the exact flight time. In marine environment to avoid sun glint in images while the sun is high up in the sky, it is recommended to tilt the sensor to an angle of 15-20 degrees off-nadir or to set the flight path in the direction or the opposite direction of the sun azimuth [29,30]. On the other side when using multispectral images, sun glint correction methods are existing and described in the literature [31,32].…”

Measuring Change Using Quantitative Differencing of Repeat Structure-From-Motion Photogrammetry: The Effect of Storms on Coastal Boulder Deposits

“…UAVs and structure-from-motion (SfM) photogrammetric software have become go-to tools for monitoring hazardous locations such as landslides [6][7][8][9][10][11][12] and subsidence/sinkholes [13][14][15]. These technologies have also been widely adopted in coastal erosion [16][17][18], marine science [19][20][21], both marine and terrestrial ecology [22][23][24][25][26][27], archaeology [28][29][30][31][32][33][34][35], and civil engineering [36][37][38][39][40].…”

Use of Drones in Fishery Science

“…The variety of platforms has rapidly increased and the costs have fallen for most types of UASs, making the barrier to entry lower than it has been in the past. Generally speaking, first‐time users should strongly consider purchasing the smallest and cheapest UAS that will fulfill their project requirements to ease operational and budgetary concerns (Joyce et al., in press). See Watts et al.…”