comparisons to be made between satellite imagery and CASI, three considerations were made: (1) Data for use in habitat categorisation were drawn from a wide area to represent the range of habitats present in all image types (2) To obtain replicate pixels of each habitat type and mitigate spatial autocorrelation (Cli and Ord 1973), a larger area was visited for satellite sensors than for CASI (i.e. a single seagrass bed may represent hundreds of CASI pixels but only a few, relatively autocorrelated pixels in a satellite image) (3) The high costs associated with flying and processing CASI dictated that only a relatively small area of Caicos Bank could be surveyed. Cockburn harbour was chosen because most habitats were represented in a microcosm of the bank (Fig. 1: inset).