Comparison of Sentinel-2 and Landsat-8 OLI satellite images vs. high spatial resolution images (MIVIS and WorldView-2) for mapping Posidonia oceanica meadows

Mediterranean seagrasses are represented by five species, whose most representative are Posidonia oceanica (L.) Delile and Cymodocea nodosa (Ucria) Ascherson. Spatial data analysis through remote sensing techniques is certainly a useful tool in order to understand and quantify the extent or loss of seagrass areas. Seagrass mapping and monitoring by remote sensing have been established using various optical remote sensors and mapping methods1. In most studies for habitat mapping, the most common satellite images used are Landsat, Ikonos, Quickbird, Pleiades, World View 2 and the recent Sentinel-2 etc. 1-2. The aim of this work is to compare the spatial accuracy of medium – resolution satellite images (Sentinel-2 and Landsat-8 OLI) vs. high-resolution images (MIVIS and WorldView-2) for mapping P. oceanica meadows and evaluating their conservation status. The present study was conducted in 2016 within the MPA “Capo Rizzuto” (Mediterranean Sea - Southern Ionian Sea). Remote sensing images were processed following several stages such as preprocessing phase, segmentation, supervised classification and accuracy classification assessment. Preliminary results highlighted differences in spatial and thematic accuracy between medium and very high spatial resolution images for seagrass habitat mapping.