Interpretation of bottom types from IKONOS satellite images of the Southern Key West National Wildlife Refuge, Florida, USA.

Remote sensing of coastal marine environments has long challenged coastal researchers who have searched for automated methods based on supervised classifications. Due to complexities in water clarity and attenuation of spectral reflection with water depth, this study focused on visual interpretation of IKONOS satellite images in an effort to ascertain the general nature of bottom types. Development of a seafloor topology for a portion of the Key West National Wildlife Refuge in Monroe County, Florida (between Key West, Florida, and the Dry Tortugas) resulted in 96 mapping units. The natural complexity of this environment required classification units that were defined by numeric codes that were keyed to a classification system developed for this area. These units, defined in a stepwise procedure, were predicated on the geomorphologic base, context of the geomorphological zone, biological cover, and percentage of that cover. The GIS attribute table, built with a multi-discipline interpretation in mind, was constructed to allow end user flexibility when extracting the information related to major biological cover, detailed geological cover, etc. Suffixes were added to further interpret areas with diverse biological cover. The IKONOS satellite images were found to be useful tools for mapping coastal marine environments at a nominal scale of 1:6000.