2000 Photo Mosaics and Hyperspectral Imagery for the Main Eight Hawaiian Islands Utilized to Map Shallow Water Benthic Habitats

This project is a cooperative effort among the National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Monitoring and Assessment; the University of Hawaii; and Analytical Laboratories of Hawaii, LLC. The goal of the work was to develop coral reef mapping methods and compare benthic habitat maps generated by photointerpreting georeferenced color aerial photography and hyperspectral imagery. Aerial photographs were acquired for the Main Eight Hawaiian Islands Benthic Mapping Project in 2000 by NOAA Aircraft Operation Centers aircraft and National Geodetic Survey cameras and personnel. Approximately 1,500, color, 9 by 9 inch photos were taken of the coastal waters of the Main Eight Hawaiian Islands at 1:24,000 scale. Specific sun angle and maximum percent cloud cover restrictions were adhered to when possible during photography missions to ensure collection of high quality imagery for the purpose of benthic mapping. In addition, consecutive photos were taken at 60 percent overlap on individual flight lines and 30 percent overlap on adjacent flight lines to allow for orthorectification and elimination of sun glint. The enhanced spectral resolution of hyperspectral and control of bandwidths of multispectral data yield an advantage over color aerial photography particularly when coral health and time series analysis of coral reef community structure are of interest. The AURORA hyperspectral imaging system collected 72 ten nm bands in visible and near infrared spectral range with a 3 meter pixel resolution. The data was processed to select band widths, which optimized feature detection in shallow and deep water. The digital scans of aerial photos and hyperspectral imagery were orthorectified to eliminate sources of spatial distortion. With these orthorectified images photointerpreters can accurately and reliably delineate boundaries of features in the imagery as they appear on the computer monitor using a software interface such as the Habitat Digitizer.