Science and technology/Technology and engineering/IT-computer sciences
Substrate and benthic habitat map of the southern Adriatic Sea (Italy) using RSOBIA - Supplementary material.
Data, workflow and results of the RSOBIA analysis carried out on the Southern Adriatic Sea CNR-ISMAR datasets
Substrate and benthic habitat map of the southern Adriatic Sea (Italy) using RSOBIA - Supplementary material
Mariacristina PRAMPOLINI, Mariacristina PRAMPOLINI, and Valentina Grande. "Substrate and benthic habitat map of the southern Adriatic Sea (Italy) using RSOBIA - Supplementary material." ROHub. Apr 29 ,2021. https://w3id.org/ro-id/a21484de-74d2-4fd0-9518-d3faa42130ad.
A huge amount of multibeam backscatter data has been acquired from the east to the west side of thein the southern Adriatic Sea in the last 15 years and coveringby CNR âISMAR. from the continental shelf down to the basin floor, from the west to east side of the Adriatic Basin. These data have been used for geological, biological and habitat mapping purposes, but a single and consistent interpretation of all the acquired backscatter data has never been carried out. Here, we aimed at coherently interpreting the seafloor reflectivity datasets in order to produce aseabed and benthic habitat maps of the southern Adriatic Sea showing the spatial distribution of substrate and sediment type and grain size within the basin. The methodology here applied consists of a semi-automated classification of backscatter images through object-based image analysis (OBIA) performed through the ArcGIS tool RSOBIA (Remote Sensing OBIA). This unsupervised image segmentation was carried out on each backscatter dataset separately and then validated through comparison with bottom samples and images acquired during the different oceanographic cruises. The substrate was then classified following the a classification scheme proposed within the CoCoNet specifically elaborated in-house project. The results were described and discussed as well as the methodology applied and the significance of the backscatter data in general.
The workflow consits of three steps: 1. RSOBIA segmentation Segmentation is a method to aggregate pixels together to create a thematic map. The segmentation process is a licensed tool taking a multi-layered image and creates a set of polygons defined by the statistics associated with the layered image. Clusters of the imagery pixels are created in n-dimensional space and created into classes. Aggregation into geographic regions (polygons) is done according to a minimum polygon size rule, and clustering rules. Input is a single multi-layered file â not a geodatabase. Output is a single polygon vector shapefile and its default filename is the same as the input basename but with a different filetype. 2.Add Segment Attributes Following segmentation, the attributes for each polygon only relate to the polygon shape and class. It is often required to view and use the values of initial raster layers. These can be aggregated for each polygon as an attribute value of the mean and standard deviation of the pixel values within the polygon for each layer. 3. GroundTruth Samples The attributes for each polygon can be extended if groundtruth point data is available. This is a very simple join of two datasets and effectively adds the attributes of a groundtruth data point to the relevant polygon. In this way the samples may be utilised to characterise the class type. Some polygons may not have groundtruth samples and will therefore be left blank. Hopefully enough of the polygons will have groundtruth points to inform the class descriptions.
Substrate and benthic hanitat map of the sourthern Adriatic Sea
Workflow applied in the present work visualized in Model Builder (ArcGIS 10.5) and showing the tools of RSOBIA toolset used in the present work (yellow), the input data - rasters to be seg-mented and ground-truthing data â (purple), the segmentation parameters to be chosen by the operator (light blue), the results (green) and the ArcGIS workspace (dark blue)
Samples used to classify substrates and benthic habitats
Prampolini, M.; Angeletti, L.; Castellan, G.; Grande, V.; Le Bas, T.; Taviani, M.; Foglini, F. Benthic Habitat Map of the Southern Adriatic Sea (Mediterranean Sea) from Object-Based Image Analysis of Multi-Source Acoustic Backscatter Data. Remote Sens. 2021, 13, 2913. https://doi.org/10.3390/rs13152913
Backscatter acquired with Reson Seabat 7160