Providing accurate maps of coral reefs where the spatial scale and labels of the mapped features correspond to map units appropriate for examining biological and geomorphic structures and processes is a major challenge for remote sensing. The objective of this work is to assess the accuracy and relevance of the process used to derive geomorphic zone and benthic community zone maps for three western Pacific coral reefs produced from multi-scale, object-based image analysis (OBIA) of high-spatial-resolution multi-spectral images, guided by field survey data. Three Quickbird-2 multi-spectral data sets from reefs in Australia, Palau and Fiji and georeferenced field photographs were used in a multi-scale segmentation and object-based image classification to map geomorphic zones and benthic community zones. A per-pixel approach was also tested for mapping benthic community zones. Validation of the maps and comparison to past approaches indicated the multi-scale OBIA process enabled field data, operator field experience and a conceptual hierarchical model of the coral reef environment to be linked to provide output maps at geomorphic zone and benthic community scales on coral reefs. The OBIA mapping accuracies were comparable with previously published work using other methods; however, the classes mapped were matched to a predetermined set of features on the reef.

The aim of this study was to create a seagrass presence/absence map for the optically complex waters of Moreton Bay. The capability to map seagrass meadows in waters of varying clarity using a consistent and repeatable method is an invaluable resource for conservation and management of seagrass regionally and globally. The map was created using an adaptation of a Google Earth Engine (GEE) cloud processing and machine learning algorithm which for seagrass, utilized citizen science spot check field data, Landsat 8 OLI imagery pulled directly from GEE, a bathymetry layer (30 m), slope derived from depth and a coral mask. This dataset consists of a shapefile that shows seagrass presence (≥ 25 % cover) and substrate mapped simultaneously for the turbid waters of the Western Bay coastline and the optically clear waters of the Eastern Banks, Moreton Bay, Queensland, Australia. This record contains a snapshot of the data taken for use in Seamap Australia (a national benthic habitat map; https://seamapaustralia.org). View the original record at: https://doi.pangaea.de/10.1594/PANGAEA.937501