[ Bathymetry | Backscatter | Optical Validation | Seafloor Characterization ]
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Substrate: The Seafloor substrate (i.e., hard vs. soft bottom) around islands/atolls in Pacific Remote Island Areas produced by the NOAA Ecosystem Sciences Division (ESD). The islands/atolls include Howland, Baker, Jarvis, Kingman Reef, Palmyra Atoll, Johnston Atoll, Wake Atoll. This is a preliminary product derived from an unsupervised classification of ship-based multibeam echo-sounder (MBES) bathymetry and backscatter data, or Worldview Imagery. These multibeam data or Worldview images were preprocessed accordingly and unsupervised classification segmented them into multiple classes, and the binary substrate map was produced by mapping interpreter’s informed judgments in attributing the predicted classes. Where required, area-specific class attribution and minor manual editing were undertaken to remove inaccurate predictions. Cell values reflect whether the seafloor is hard or soft. Please see the associated metadata for additional information.
Substrate- Hard bottom vs. Soft bottom – 2 meter grid
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Hard bottom vs. Soft bottom Substrate Classification Data Files
- GeoTIFFs: Metadata text • Zipped data
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Substrate- Hard bottom vs. Soft bottom – 40 meter grid
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Hard bottom vs. Soft bottom Substrate Classification Data Files
- GeoTIFFs: Metadata text • Zipped data
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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 of image, and 4) explanatory metadata text file (identical to linked file listed below).
Slope – 20 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.
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Slope data files
- Arc ASCII: Metadata text • Zipped data
Rugosity – 20 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)
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Rugosity data files
- Arc ASCII: Metadata text • Zipped data
BPI Structures – 20 meter grid
BPI Structures: Derived from two scales (20 & 250) of BPI; slope; and depth. Three ranges of slope defined flats, slopes and near vertical: x < 5; 5 < x < 70. Depth alone, in this case, is added only to separate flat structures into shelf (<30 m) and broad flat (>30 m) environments (depths based on SCUBA limits).
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| A visual description of BPI Structure classes (Click image for larger view.) |
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BPI Structures data files
- Arc ASCII: Metadata text • Zipped data
BPI Zones – 20 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.
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BPI Zones data files
- Arc ASCII: Metadata text • Zipped data