Coral reefs are classified by estimated present threat from local human activities, according to the Reefs at Risk integrated local threat index. The index combines the threat from the following local activities: overfishing and destructive fishing, coastal development, watershed-based pollution, and marine-based pollution and damage.
Base data source: Reef locations are based on 500 meter resolution gridded data reflecting shallow, tropical coral reefs of the world. Organizations contributing to the data and development of the map include the Institute for Marine Remote Sensing, University of South Florida (IMaRS/USF), Institut de Recherche pour le Développement (IRD), UNEP-WCMC, The World Fish Center, and WRI. The composite data set was compiled from multiple sources, incorporating products from the Millennium Coral Reef Mapping Project prepared by IMaRS/USF and IRD.
Map projection: Lambert Cylindrical Equal-Area; Central Meridian: 160° W.