Alamagan Island: Geomorphology

[ Bathymetry | Backscatter | Optical Validation | Geomorphology ]
Download 10 meter grid:
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 of image, and 4) explanatory metadata text file (identical to linked file listed below).

Slope – 10 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
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Rugosity – 10 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

BPI Structures – 10 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).

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

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BPI Structures data files

BPI Zones – 10 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
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