Benthic Habitat Data

Bathymetry

5m grid data

Backscatter Imagery

Not yet available

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 files

CNMI-Guam: 35 & 37 fthm Banks

[ Bathymetry | Backscatter | Optical Validation | Geomorphology ]

Gridded Geomorphology

Slope, Rugosity, BPI Structures & Zones

Click here for a Discussion of Geomorphological Layers

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. Results indicate that both banks are flat-topped, with maximum slope on the bank top being 10 degrees, and most of the bank top having less than 5 degrees slope.

Image map of Guam slope.

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Slope data files
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Rugosity - 5 meter grid

Rugosity: 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 and convolutedness. (Jenness 2003). Results indicate very low rugosity across both bank tops.

Image map of Guam rugosity.

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Rugosity data files
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BPI Structures and Zones

Bathymetric Positioning Index (BPI) structures and zones are calculated from the relative bathymetric position (elevation) of adjacent cells in a bathymetric grid. As the slope and rugosity maps above show, there is too little change in elevation on the two banks to create distinct bathymetric zones or structures using the existing classification dictionary, and as a result the entire banktops would be classified as ‘flats’. Therefore these two products have not been created here. 

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