The most widespread use of satellite imagery has been the mapping and inventory of coastal resources (e.g. Ku- chler et al. 1986; Bastin 1988; Luczkovich et al. 1993). Maps of reef habitat are a useful planning tool which, among other uses, allows management boundaries to be located (Kenchington and Claasen 1988) and the iden- tification of representative reef systems (McNeill 1994). This paper is specifically concerned with the use of remote sensing for mapping coral-reef systems.