Scientiﬁc exploration of seabed substrata has signiﬁcantly progressed in the last few years. Hydroacoustic methods of seaﬂoor investigation, including multibeam echosounder measurements, allow us to map large areas of the seabed with unprecedented precision. Through time-series of hydroacoustic measurements, it was possible to determine areas with distinct characteristics in the inlets of the Lagoon of Venice, Italy. Their temporal variability was investigated. Monitoring the changes was particularly relevant, considering the presence at the channel inlets of mobile barriers of the Experimental Electromechanical Module (MoSE) project installed to protect the historical city of Venice from ﬂooding. The detection of temporal and spatial changes was performed by comparing seaﬂoor maps created using object-based image analysis and supervised classiﬁers. The analysis included extraction of 25 multibeam echosounder bathymetry and backscatter features. Their importance was estimated using an objective approach with two feature selection methods. Moreover, the study investigated how the accuracy of classiﬁcation could be aﬀected by the scale of object-based segmentation. The application of the classiﬁcation method at the proper scale allowed us to observe habitat changes in the tidal inlet of the Venice Lagoon, showing that the sediment substrates located in the Chioggia inlet were subjected to very dynamic changes. In general, during the study period, the area was enriched in mixed and muddy sediments and was depleted in sandy deposits. This study presents a unique methodological approach to predictive seabed sediment composition mapping and change detection in a very shallow marine environment. A consistent, repeatable, logical site-speciﬁc workﬂow was designed, whose main assumptions could be applied to other seabed mapping case studies in both shallow and deep marine environments, all over the world.
|Data di pubblicazione:||2020|
|Titolo:||Spatial and Temporal Changes of Tidal Inlet Using Object-Based Image Analysis of Multibeam Echosounder Measurements: A Case from the Lagoon of Venice, Italy|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.3390/rs12132117|
|Appare nelle tipologie:||2.1 Articolo su rivista |