IKONOS Imagery for the Main Eight Hawaiian Islands: Hawaii (421-0824)

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, hyperspectral and IKONOS satellite imagery.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. Multispectral (blue/green/red/near-infrared) IKONOS imagery was obtained at a four meter pixel resolution. The IKONOS imagery was processed to minimize atmospheric and water column effects. 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.

The National Ocean Service is conducting research to digitally map biotic resources and coordinate a long-term monitoring program that can detect and predict change in U.S. coral reefs, and their associated habitats and biological communities.

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The National Oceanic and Atmospheric Administration (NOAA), National Centers for Coastal Ocean Science (NCCOS), Biogeography Program produced this data CD-ROM. NCCOS Biogeography Program does not guarantee the accuracy of the geographic features or attributes.

Project Information is available online, or on CD-ROM through the NCCOS Biogeography Program.;

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All of the IKONOS imagery was purchased in National Imagery Transmission Format (NTIF) with the associated Rational Polynomial Coefficients (RPCs). When using image analysis software capable of reading NITF files with associated RPCs, the horizontal positioning error never exceeded 15 m (for locations where there is little or no vertical relief to affect image pixel displacement. The IKONOS imagery swaths, were mosaicked to within one pixel width, and were processed to minimize atmospheric effects and compensate for water column effects.

The IKONOS imagery were optimized to maximize true color and during the map preparation the color was strategically manipulated to extract the most habitat information. The IKONOS satellite imagery were processed to remove atmospheric effects and compensate for water column effects.

All of the IKONOS images were collected with collection angles of less than 20 degrees from nadir. Constraining the collection angle is important because positioning features on the seabed using satellite imagery is affected by refraction of light through the water column. When the collection angle is limited to less than 20 degrees, the maximum offset of seabed features would be less than 4 m in water less than 15 m deep and less than 8 m in water less than 30 meters deep.