Seafloor character--Hueneme Canyon and Vicinity, California

The seafloor-character map was produced using video-supervised maximum likelihood classification of the bathymetry and backscatter intensity of return from sonar systems. The classification was supervised using signatures defined by hand-drawn polygons located through sediment samples and video-observation ground-truthing, applying methodology described in Cochrane (2008), available at http://doc.nprb.org/web/research/research%20pubs/615_habitat_mapping_workshop/Individual%20Chapters%20High-Res/Ch13%20Cochrane.pdf. The two variants used in this classification were backscatter intensity and derivative rugosity. Rugosity measures terrain ruggedness as the variation in three-dimensional orientation of grid cells within a neighborhood. Vector analysis is used to calculate the dispersion of vectors normal (orthogonal) to grid cells within the specified neighborhood. This method effectively captures variability in slope and aspect into a single measure. Ruggedness values in the output raster map can range from 0 (no terrain variation) to 1 (complete terrain variation). The calculation was performed using the Terrain Ruggedness (VRM) tool (for details, see Sappington and others, 2007). Classes I, II, and III were delineated using multivariate analysis. Class IV values were depicted on the basis of visual identification using both bathymetry and backscatter (slight depression in the seafloor, very high backscatter return). The resulting map (gridded at 2 m) was cleaned by hand to remove data-collection artifacts (for example, trackline nadir). Editing was performed in Photoshop, with which individual pixels were selected and values adjusted to remove noise. Selection occurred without antialiasing, and the resulting grid was identical but for the edited pixels. The four seafloor classes were then colored to indicate which of the five California MLPA depth zones they are located in: Depth Zone 2 (intertidal to 30 m), Depth Zone 3 (30 to 100 m), Depth Zone 4 (100 to 200 m), or Depth Zone 5 (greater than 200 m). These were further subdivided into one of the following slope classes: Slope Class 1 (0 degrees-5 degrees), Slope Class 2 (5 degrees-30 degrees), Slope Class 3 (30 degrees-60 degrees), or Slope Class 4 (60 degrees-90 degrees). Depth Zone 1 (intertidal) is not represented in the region covered by this block.

Metadata was modified to bring up to current USGS PCMSC standards. Information for accompanying Scientific Investigations Report added to Abstract and Cross Reference sections. Point of Contact information was updated. USGS Thesaurus and keywords were added, and Process Steps were refined. Details about different Network Resource Name links was given in the Access Instructions section. Phone number for Metadata Contact was corrected. Minor typos were corrected. No data information was changed.