3-D Benthic Terrain Mapping and Modeling in American Samoa

2005 Association of American Geographers Annual Meeting
April 5-9, 2005, Denver, CO

SPECIAL SESSION: Marine/Coastal GIS and Acoustic Remote Sensing

R Rinehart

Dept of Geosciences, Oregon State Univ

Corvallis, OR 97331-5506

541-737-8818

DJ Wright

Dept of Geosciences, Oregon State Univ

Corvallis, OR 97331-5506

541-737-1229

J Murphy and L Cary-Kothera

NOAA Coastal Services Center

Charleston, SC

E Lundblad

Dept of Geosciences, Oregon State Univ

Corvallis, OR 97331-5506

now at NOAA Coral Reef Ecosystem Division

Honolulu, HI

E Larkin

Dept of Geosciences, Oregon State Univ

Corvallis, OR 97331-5506

now with Knauss Marine Policy Fellowship Program

Silver Spring, MD

Ongoing has been the development of a systematic and robust methodology by which acoustic multibeam bathymetric data can be transformed into a classified product that is useful for coastal and marine resource managers, scientists and educators in American Samoa. GIS analyses for benthic terrain consider slope, aspect, rugosity, bathymetry, and bathymetric position index as factors. Based on this methodology Oregon State University and the NOAA Coastal Services Center have developed the Benthic Terrain Modeler (BTM), a new ArcGIS 8.x extension. The BTM also incorporates a scalable classification dictionary that can be used to maintain consistency across multiple levels of a seafloor mapping project. Included with the tool is a default classification schema that can be customized through one of the tool's steps or through direct editing of the classification dictionary file which is in the Extensible Mark-up Language (XML) format. The extension's wizard interface educates and guides the user through a series of analysis steps, resulting in a classified terrain that may be suitable for tying to benthic species distributions for the preparation of habitat maps. This methodology has been used to produce some of the first benthic terrain maps and 3-D visualizations for several coastal locations in American Samoa including the Fagatele Bay National Marine Sanctuary. Maps generated by the BTM have been further enhanced with data from towed-diver survey tracts and accuracy assessment points. Successful incorporation of these data sources will move beyond a purely geomorphological description of the benthoscape toward a biotic benthic community assemblage focused assessment.

Keywords: coastal/marine GIS, benthic habitat, coral reefs, seafloor mapping

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