A comparison between UAV and high-resolution multispectral satellite images for bathymetry estimation

We proudly share this interesting study on the application of multispectral survey to the bathymetric depth estimation. The study was carried out by Italian professionals in the field of remote sensing and geomatic survey using our multispectral camera MAIA WV, which has 8 bands with the same wavelength intervals as Digital Globe’s WorldView-2 satellite. The study led to the estimation of the depth and bathymetric trend of shallow seabed close to the coast. Here is the abstract of their publication with AIT – Italian Association of Remote Sensing.

Shallow water bathymetric surveys support Integrated Coastal Zone Management and Maritime Spatial Planning, e.g. in coastal erosion monitoring, shore protection design and landfall projects oil and gas pipelines. High-resolution multispectral satellite imagery, such as Quick Bird and Worldview, are increasingly used for this purpose. The present study shows the results of a comparison between high resolution satellite and Unmanned Aerial Vehicle (UAV) derived bathymetry. Accuracy was validated through an hydrographic survey performed with a Multibeam Echosounder (MbEs) at the same time of UAV acquisition. The drone was equipped with a small and light multispectral camera, acquiring in the same WorldView-2 sensors spectral bands. The study area, located in the central Tuscany coast (Italy), is approximately 0.5 km2. Because of the high percentage of water present in UAV images, a new method was implemented to produce a georeferenced orthophoto mosaic. Multispectral images were processed to retrieve bathymetric data with Stumpf’s algorithm. Different pairs of bands were tested to determine the best fit for real water depth data. The influence of sea bottom control points density on data accuracy was also analyzed. Results show the possibility to produce accurate remote sensing bathymetric maps with low operational costs and easy data processing, giving the chance to set up shallow water monitoring programs based on UAV surveys. A further advantage of this method is the capability to produce a full sea-floor
coverage bathymetry in very shallow water areas, were MbEs is usually unable to work properly and to represent the aerial option to survey very shallow waters alternatively to Unmanned Surface Vehicles (USV) a.k.a. ASV (autonomous surface vehicles).

Here below you can read and download the paper.

A comparison between UAV and high-resolution multispectral satellite images for bathymetry estimation

L. Rossi – Dept. of Earth Science, University of Florence, Italy  and  GeoCoste snc, Florence, Italy

I. Mammi – Dept. of Earth Science, University of Florence, Italy

E. Pranzini – Dept. of Earth Science, University of Florence, Italy