Benthic Habitat Mapping
DATA BY LOCATION
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).
Substrate :This is a preliminary product 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.
GeoTIFFs derived separately from Simrad em3002d and Reson 8101 backscatter:
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.
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)
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).
|A visual description of BPI Structure classes (Click image for larger view.)|
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.