Entity_Type:
Entity_Type_Label: SeafloorCharacter_OffshorePacifica.tif.vat
Entity_Type_Definition:
The shapefile attributes include VALUE - code for the seafloor character classes, COUNT - number of pixels, SLOPE - slope classes, DEPTH_ZONE - depth zones, SUBSTRATE - substrate classes, SUBST_DESC - short description of substrate classes, and FULL_DESC - detailed description of substrate classes. The shapefile can be added to any ESRI ArcMap project.
Entity_Type_Definition_Source: ESRI
Attribute:
Attribute_Label: Rowid
Attribute_Definition: Internal feature number.
Attribute_Definition_Source: ESRI
Attribute_Domain_Values:
Unrepresentable_Domain:
Sequential unique whole numbers that are automatically generated.
Attribute:
Attribute_Label: VALUE
Attribute_Definition:
This seafloor-character class was produced using video-supervised maximum-likelihood classification of the bathymetry and backscatter (intensity of return) signals from sonar systems. Derivative roughness (rugosity) and backscatter intensity were used as variants in the classification. The resulting four substrate classes (1-4) were divided into the Depth Zones (see Attribute: DEPTH_ZONE) by adding to the original grid value in increments of 10. Depth Zone 2, add 0 to grid value; Depth Zone 3, add 10 to grid value; Depth Zone 4, add 20 to grid value; and Depth Zone 5, add 30 to grid value. The resulting grid was further classified into Slope Classes (see Attribute: SLOPE) by adding to the classified raster values (including depth zones) in increments of 50. Slope Class 1, add 0 to grid value; Slope Class 2, add 50 to grid value; Slope Class 3, add 100 to grid value; and Slope Class 4, add 150 to grid value.
Attribute_Definition_Source: ESRI
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1
Range_Domain_Maximum: 14
Attribute_Units_of_Measure: Integers 1 - 14 representing seafloor character classes.
Attribute:
Attribute_Label: COUNT
Attribute_Definition:
The number of pixels (2m x 2m size grid cell) represented in each seafloor class (see Attribute: VALUE).
Attribute_Definition_Source: ESRI
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 81926
Range_Domain_Maximum: 19594633
Attribute_Units_of_Measure: Integers 81926 - 19594633 pixel count.
Attribute:
Attribute_Label: SLOPE
Attribute_Definition:
The slope zones for the final seafloor-character map grid were identified on the basis of the smoothed bathymetry grid. The smoothing was done by applying focal statistics to the original bathymetry grid. The tool uses a moving window and calculates the mean value of the central pixel within a circular neighborhood of 20 m radius along the whole raster map. The resulting raster map represents a smoothed value highlighting overall trends and eliminates local varieties in the terrain (such as higher slopes along rock outcrops). Slope class values are: 1 (flat; 0 degrees to 5 degrees), 2 (sloping; 5 degrees to 30 degrees), 3 (steeply sloping; 30 degrees to 60 degrees), or 4 (vertical; 60 degrees to 90 degrees), or 5 (overhang; greater than 90 degrees).
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1
Range_Domain_Maximum: 1
Attribute_Units_of_Measure:
Integer value 1 representing slope class of <5 degrees as described above.
Attribute:
Attribute_Label: DEPTH_ZONE
Attribute_Definition:
The depth zones for the final seafloor-character map grid were identified on the basis of the smoothed bathymetry grid. The smoothing was done by applying focal statistics to the original bathymetry grid. The tool uses a moving window and calculates the mean value of the central pixel within a circular neighborhood of 20 m radius along the whole raster map. The resulting raster map represents a smoothed value highlighting overall trends and eliminates local varieties in the terrain (such as varying depths along rock outcrops). Depth Zone values are: Depth Zone 1, intertidal; Depth Zone 2, intertidal to 30 m; Depth Zone 3, 30 to 100 m; Depth Zone 4, 100 to 200 m; and Depth Zone 5, deeper than 200 m (California Department of Fish and Game, 2008).
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 2
Range_Domain_Maximum: 3
Attribute_Units_of_Measure:
Integer values 2-3 representing slope classes as described above.
Attribute:
Attribute_Label: SUBSTRATE
Attribute_Definition:
Coded values of the substrate classes. Class 1, Fine- to medium-grained smooth sediment; Class 2, Mixed smooth sediment and rock; Class 3, Rock and boulder, rugose; Class 4, Medium- to coarse- grained sediment
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1
Range_Domain_Maximum: 4
Attribute_Units_of_Measure:
Integer values 1-4 representing substrate classes as described above.
Attribute:
Attribute_Label: SUBST_DESC
Attribute_Definition:
Summary description of the four substrate classes coded by the attribute SUBSTRATE. Class 1, Fine- to medium-grained smooth sediment; Class 2, Mixed smooth sediment and rock; Class 3, Rock and boulder, rugose; Class 4, Medium to coarse grained (Mobile Sed Features)
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Unrepresentable_Domain: Names are in text form, maximum length: 50
Attribute:
Attribute_Label: FULL_DESC
Attribute_Definition:
Detailed description of the four substrate classes coded by the attribute SUBSTRATE. Class 1, Low backscatter, low rugosity, typically mud to medium-grained sand, often rippled and/or burrowed; Class 2, Moderate to very high backscatter, low rugosity, typically coarse-grained sand, gravel, cobble and bedrock; Class 3, High backscatter, and high rugosity, typically boulder and rugose bedrock; Class 4, Very high backscatter, low rugosity; typically medium- to coarse-grained, rippled sediment with some shell hash in shallow depressions
Attribute_Definition_Source: USGS
Attribute_Domain_Values:
Unrepresentable_Domain: Names are in text form, maximum length: 250
