Benthic Habitats of Florida Bay, FL 1991-1995

In the winter of 1991/92 the National Oceanic and Atmospheric Administration's Office for Coastal Management's Coastal Change Analysis Program (C-CAP) and the State of Florida commissioned the National Ocean Service's Photogrammetry Unit, the National Geodetic Survey (NGS), to acquire conventional color metric aerial photography of Florida Bay suitable for interpretation of photic benthic habitats (scale of 1:48,000). Additional photography was acquired by NGS in 1995 to cover areas of the bay that were not interpretable due to turbidity and glare during the original mission. The imagery was collected according to stringent parameters detailed in the C-CAP protocol (http://www.coast.noaa.gov/crs/lca/ccap.html). The original photographic diapositives were interpreted by two ecologists, familiar with the local environment. The benthic signatures were interpreted from the photography using Bausch and Lomb Zoom Stereoscopes and Richards Light Tables. The boundaries of each unique signature were delineated on acetate overlays and assigned one of 20 habitat classes. Only the central 'sweet spot' of each frame was interpreted to minimize the effects of sun glint. An ecologist at the Florida Marine Research Institute (FMRI) conducted thematic quality assurance and control. Following interpretation, Office for Coastal Management staff scanned the aerial photos, with the interpreted acetate overlays attached, using a photogrammetric quality scanner (AGFA Horizon Plus) at a resolution of 600 dpi resulting in a pixel resolution of 2.03 meters. The resulting image file was rectified (second order bilinear interpolation) using ERDAS Imagine software. Ground control points were selected from features common to digital orthophotoquads of Florida Bay. The interpreted polygon habitats were digitized into an ARC coverage from the rectified files using ERDAS Imagine software's vector module. In 1999, the final edits and quality control of the habitat polygons were completed. The coverage and shoreline were edge matched to the Benthic Habitats of the Florida Keys Atlas to complete the coverage, as the dates of photography, methodology and classification system used were the same.