Eighteen distinct and non-overlapping biological cover types were identified that could be mapped through visual interpretation of the satellite imagery. Habitats or features that cover areas smaller than the minimal mapping unit of 1 acre were not considered. For example, uncolonized sand halos surrounding coral patch reefs are too small to be mapped independently. Cover type refers only to the predominant biological component colonizing the surface of the feature and does not address location (e.g., on the shelf or in the lagoon). The cover types are defined in a collapsible hierarchy ranging from eight major classes (live coral, seagrass, macroalgae, encrusting/coralline algae, turf algae, emergent vegetation, uncolonized, and unknown), combined with a density modifier representing the percentage of the predominant cover type (10%-<50% sparse, 50%-<90% patchy, 90%-100% continuous).