Benthic Habitat Data

Bathymetry

Zipped data files contain 1) grid data file (GMT or ASCII), 2) high-res JPG of image, and 3) explanatory metadata text file (identical to linked file listed below).

5m grid data
Merged Multibeam Bathymetry, IKONOS Derived Depths

Backscatter Imagery

Optical Validation

Geomorphology

Zipped data files contain 1) Arc ASCII file, 2) layer (.lyr) file for symbology, 3) high-res JPG of image, and 4) explanatory metadata text file (identical to linked file listed below).

5m grid data

American Samoa:Ofu and Olosega

[ Bathymetry | Backscatter | Optical Validation | Geomorphology ]

Gridded Geomorphology

Download 5 meter grid:
Substrate, Slope, Rugosity, BPI Structures, BPI Zones

Click here for a Discussion of Geomorphological Layers

Zipped data files contain 1) Arc ASCII file, 2) layer (.lyr) file for symbology, 3) high-res JPG/PDF of image, and 4) explanatory metadata text file (identical to linked file listed below).

Substrate- Hard bottom vs. Soft bottom - 5 meter grid

Substrate :This product is derived from an unsupervised classification of multibeam bathymetric data derivatives and multibeam backscatter data. Cell values reflect whether the seafloor is hard or soft. Please see the metadata for additional information. 

Image map of Ofu-Olosega hard vs. soft map.

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Hard bottom vs. Soft bottom Substrate Classification Data Files
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Substrate- Integrated Hard bottom vs. Soft bottom - 5 meter grid

Substrate: This is a product derived from combining the hard bottom vs. soft bottom map described above, with the shallow-water benthic habitat map for American Samoa, produced by NOAA Biogeography Branch (Center for Coastal Monitoring and Assessment, 2005). By combining these two maps, a product is created that covers the entire coral reef ecosystem from shoreline to its outer edge. The two datasets were combined by taking the ‘major structure’ attribute from the NOAA Biogeography Branch habitat map and converting this into a raster, where ‘coral reef and hardbottom’ was given the raster value for ‘hard’ and ‘unconsolidated sediment’ was given the raster value for ‘soft’ to correspond with the CRED hard vs. soft bottom raster. The two datasets were mosaicked in ArcGIS, using the NOAA Biogeography Branch shallow-water habitat map to fill in gaps in the CRED hard vs. soft substrate map. Please see the metadata for additional information.

References:

Image map of Ofu-Olosega hard vs. soft map.

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Integrated Hard bottom vs. Soft bottom Substrate Classification Data Files
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Slope - 5 meter grid

Slope: Cell values reflect the maximum rate of change (in degrees) in elevation between neighboring cells. Slope was derived with the ArcGIS Spatial Analyst extension.

Image map of Ofu-Olosega slope.

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Slope data files
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Rugosity - 5 meter grid

Rugosity:Cell values reflect the surface area / planimetric area ratio for the area contained within that cell’s boundaries. They provide indices of topographic roughness and convolutedness. (Jenness 2003)

Image map of Ofu-Olosega rugosity.

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Rugosity data files
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BPI Structures - 5 meter grid

BPI Structures: Derived from two scales (50 & 250) of BPI; slope; and depth. Three ranges of slope defined flats, slopes and near vertical: x < 5; 5 < x < 70.

Figure giving visual description of BPI Structure classes.

A visual description of BPI Structure classes (Click image for larger view.)

Image map of Ofu-Olosega BPI Structures.

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BPI Structures data files
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BPI Zones - 5 meter grid

BPI Zones: Derived from a broad scale (250) BPI grid and slope. Two ranges of slope defined flats and slopes: x < 5 and 5 < x < 70.

Image map of Ofu-Olosega BPI Zones.

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BPI Zones data files
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