Rugosity is derived from gridded (5 m cell size) multibeam bathymetry, collected aboard NOAA Ship Hiialaka'i and R/V AHI, using the Benthic Terrain Modeler with rugosity methods by Jeff Jenness (2003). Cell values reflect the surface area and (surface area) / (planimetric area) ratio for the area contained within that cell's boundaries. They provide indices of topographic roughness & convolutedness. This data set is for the shelf and slope environments of Tutuila Island, American Samoa, South Pacific.
The data were derived in support of NOAA Coral Reef Conservation Program goals. Goal 1 is to map all U.S. Coral Reef Ecosystems. This data set specifically addresses Objective 1 and 4: to develop high-resolution benthic maps and to characterize priority deep water reefs and associated habitats. This derivative of bathymetry provides a GIS layer that may be used for benthic and essential fish habitat characterization, and for the study of geologic features. By combining the dataset with bathymetry, backscatter, other derivatives, and in situ data, they collectively compose benthic habitat maps which are designed to be used to understand and predict moderate depth (~20m - 150m) benthic habitats for different organisms that inhabit coral reef ecosystems.
Gridded multibeam data were collected aboard the Hi'ialakai, a 218 foot United States National Oceanographic and Atmospheric Administration (NOAA) research ship, and aboard the R/V AHI (Acoustic Habitat Investigator), a 25 foot survey launch owned and operated by the NOAA Pacific Islands Fisheries Science Center in Honolulu, HI. The metadata for the bathymetry is documented in the product metadata, Tutuila_5m.asc.txt. (http://www.soest.hawaii.edu/pibhmc/ pibhmc_AmSamoa_tutuila_bathy.htm#5meter) References: Jenness, J. 2003. Grid surface areas: Surface area and ratios from elevation grids [Electronic manual]. Jenness Enterprises: ArcView Extensions. http://www.jennessent.com/arcview/arcview_extensions.htm Lundblad et al., 2006, A benthic terrain classification scheme for American Samoa, Marine Geodesy, 29(2):89 - 111. http://www.csc.noaa.gov/products/btm/
ground condition
These data are not to be used for navigation purposes. Please acknowledge the NOAA Pacific Islands Fisheries Science Center (PIFSC) Coral Reef Ecosystem Division (CRED) and the Pacific Islands Benthic Habitat Mapping Center, and the Joint Institute for Marine and Atmospheric Research (JIMAR) and School of Ocean and Earth Science and Technology (SOEST), University of Hawaii as the sources of this information.
NOAA IRC
NMFS/PIFSC/CRED
1845 WASP Blvd., Building 176
e-mail preferred
http://www.soest.hawaii.edu/pibhmc/amsamoa_images/Tutuila_5m_Rugosity_445.jpg
NOAA PIFSC CRED and the Pacific Islands Benthic Habitat Mapping Center, JIMAR and SOEST
Data are collected for resource management and research purposes and are tested for internal consistency; however, no effort is made to compare these data to external references or to other published data.
These data are believed to be logically consistent though no tests were performed
Complete
Horizontal positioning system: GPS C/A Horizontal position accuracy: 25 meters
Range resolution of sonar: varies with depth Raw sounding resolution: varies with depth Vertical accuracy of gridded product ~ 1% of water depth
Rugosity was derived from the gridded multibeam bathymetry (Tutuila_5m) using the Benthic Terrain Modeler (BTM). The BTM may be downloaded from http://www.csc.noaa.gov/products/btm/. The BTM, written for ArcGIS 8.x or 9.x, includes a component for deriving rugosity using methods by Jeff Jenness as he wrote for ArcView 3.x.
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These data are not to be used for navigational purposes. NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
Arc ASCII can be converted to Arc Raster using ArcToolbox Conversion Tools (ASCIItoRaster).
