C.A. Endris
H.G. Greene
Center for Habitat Studies, Moss Landing Marine Laboratories
2013
Habitat--Offshore of Ventura, California
vector digital data
Samuel Y. Johnson
Peter Dartnell
Guy R. Cochrane
Nadine E. Golden
Eleyne L. Phillips
Andrew C. Ritchie
Rikk G. Kvitek
H. Gary Greene
Lisa M. Krigsman
Charles A. Endris
Gordon G. Seitz
Carlos I. Gutierrez
Ray W. Sliter
Mercedes D. Erdey
Florence L. Wong
Mary M. Yoklavich
Amy E. Draut
Patrick E. Hart
Susan A. Cochran
2013
California State Waters Map Series--Offshore of Ventura, California
map
Scientific Investigations Map
SIM 3254
Reston, VA
U.S. Geological Survey
https://pubs.usgs.gov/sim/3254/
Nadine E. Golden
2013
California State Waters Map Series Data Catalog
database
Data Series
DS 781
Reston, VA
U.S. Geological Survey
https://pubs.usgs.gov/ds/781/
This part of SIM 3254 presents data for the habitat map of the seafloor (see sheet 7, SIM 3254) of the Offshore of Ventura map area, California. The vector data file is included in "Habitat_OffshoreVentura.zip," which is accessible from https://pubs.usgs.gov/ds/781/OffshoreVentura/data_catalog_OffshoreVentura.html.
Using multibeam echosounder (MBES) bathymetry and backscatter data, potential marine benthic habitat maps were constructed. The habitats were based on substrate types and documented or "ground truthed" using underwater video images and seafloor samples obtained by the USGS. These maps display various habitat types that range from flat, soft, unconsolidated sediment-covered seafloor to hard, deformed (folded), or highly rugose and differentially eroded bedrock exposures. Rugged, high-relief, rocky outcrops that have been eroded to form ledges and small caves are ideal habitat for rockfish (Sebastes spp.) and other bottom fish such as lingcod (Ophiodon elongatus). Habitat map is presented in a map format generated in a GIS (ArcMap), and both digital and hard-copy versions will be produced.
This work is one of nine potential marine benthic habitat maps characterized after Greene and others (1999, 2007). These maps will be interpreted from MBES data collected by the CSMP in the Santa Barbara Channel area and elsewhere along the coast of central California.
Data used for the creation of the potential marine benthic habitat interpretation consists of multibeam bathymetry, acoustic backscatter, sediment samples, camera-sled imagery, and existing geologic and seafloor interpretive maps. All data were compiled and displayed for interpretation using ESRI ArcGIS software, ArcMap v.9.3. The process consists of editing a shapefile within ArcMap, beginning with the construction of polygons to delineate benthic features. A benthic feature is an area with common characteristics which can be characterized as a single potential habitat type. The boundaries and extents of these features were determined from the bathymetric data. In general, interpretations were made at scales between 1:2,000 and 1:5,000. The USGS kindly provided the Center for Habitat Studies with a geodatabase consisting of feature datasets delineating geologic features and attributes for the Santa Barbara Channel. Some of the delineated polygons were preserved as part of the potential marine benthic habitat characterization. However, the Greene and others (2007) code was used in attributing the dataset and additional polygons were added using the methods outlined below. High-resolution multibeam sonar data in the form of bathymetric depth grids (seafloor digital elevation models, referred to as the "bathymetry") were the primary data used in the interpretation of potential habitat types. Shaded-relief imagery ("hillshade") allows for visualization of the terrain and interpretation of submarine landforms. On the basis of these hillshades, areas of rock were identified by their often sharply defined edges and high relative relief; these may be contiguous outcrops, isolated parts of outcrop protruding through sediment cover (pinnacles), or isolated boulders. Although these types of features can be confidently characterized as exposed rock, it is not uncommon to find areas within or around the rocky feature that appear to be covered by a thin veneer of sediment. These areas are identified as "mixed" induration, containing both rock and sediment. Broad areas of the seafloor lacking sharp and angular characteristics are considered to be sediment. Sedimentary features may contain erosional or depositional characteristics recognizable in the bathymetry, such as dynamic bedforms (dunes or sand waves). General morphologic features such as scours, mounds, and depressions were also identified using the hillshade imagery. The combination of acoustic backscatter data and "ground truthed" sediment samples were used to delineate seafloor sediment types within areas identified as "soft (s)" induration. Initially, ground truth data, in the form of grab sample descriptions and average grain size measurements, were categorized into four grain-size categories: mud (m), muddy sand (s/m), sand (s), and sandy gravel (s/g). Backscatter data was then classified into four intensity categories (low, med, high, very high) that are assumed to correspond to relative grain sizes. The aim was to develop an intensity classification of the seafloor that correlated with the data collected from the sediment samples. Thus, the combination of remotely observed data (acoustic backscatter) and directly observed data (sediment grab samples) translates to higher confidence in our ability to interpret broad areas of the seafloor. Nonetheless, we caution against using our sediment type interpretations as anything more than "best-guess" because of the following issues: characterization of contiguous sediment bodies is a difficult procedure because even small areas can exhibit a wide spectrum of backscatter-intensity values that lack distinct boundaries; backscatter intensity can be affected by depth, vegetation, water column conditions, and seafloor relief; and directly observed sediment data, in the form of sediment samples, represents a very small area relative to remotely observed data, requiring broad areas of interpolation. Please refer to Greene and others (2007) for more information regarding the Benthic Marine Potential Habitat Classification Scheme and the codes used to represent various seafloor features.
References Cited:
Greene, H.G., Bizzarro, J.J., O'Connell, V.M., and Brylinsky, C.K., 2007, Construction of digital potential marine benthic habitat maps using a coded classification scheme and its application, in Todd, B.J., and Greene, H.G., eds., Mapping the seafloor for habitat characterization: Geological Association of Canada Special Paper 47, p. 141-155.
Greene, H.G., Yoklavich, M.M., Starr, R.M., O'Connell, V.M., Wakefield, W.W., Sullivan, D.E., McRea, J.E., Jr., and Cailliet, G.M., 1999, A classification scheme for deep seafloor habitats: Oceanologica Acta, v. 22, no. 6, p. 663-678.
2013
Publication Date
none planned
-119.447481
-119.263216
34.359236
34.214948
Global Change Master Directory (GCMD)
Oceans > Bathymetry/SeafloorTopography > Bathymetry
Oceans > Bathymetry/SeafloorTopography > Seafloor Topography
ISO 19115 Topic Category
geoscientificinformation
environment
oceans
imageryBaseMapsEarthCover
Multibeam bathymetry
General
Benthic marine habitat
Seafloor mapping
Offshore geology
GIS
Geographic Names Information System (GNIS)
Pacific Ocean
California
Santa Barbara Channel
Ventura County
Ventura
Ventura Harbor
Santa Clara River
If physical samples or materials are available, constraints on their on-site access
are described in "WR CMG Sample Distribution Policy" at URL:
http://walrus.wr.usgs.gov/infobank/programs/html/main/sample-dist-policy.html
This information is not intended for navigational purposes.
Read and fully comprehend the metadata prior to data use. Uses of these
data should not violate the spatial resolution of the data. Where
these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data.
Acknowledge the Center for Habitat Studies, Moss Landing Marine Laboratories in products derived from these data. Share data products developed using these data with the U.S. Geological Survey.
This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.
Center for Habitat Studies, Moss Landing Marine Laboratories
H. Gary Greene
Geologist/Principal Investigator
physical address
Center for Habitat Studies
Moss Landing Marine Labs
CA
95039
USA
(831) 771-4141
(831) 633-7264
greene@mlml.calstate.edu
Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcGIS 10.0.3.3600
Map elements were visually checked for overshoots,
undershoots, duplicate features, polygon closure, and other errors by the
lead authors and by the GIS technician(s) who created the digital database.
Review drafts of the map were reviewed internally by at least two other geologists for consistency
with basic geologic principles and general conformity to USGS mapping
standards.
Contact authors for information about omissions, selection criteria, generalization, definitions used, and other rules used to derive the data set.
Interpretation and polygon delineation of habitats performed at scales from 1:2000 to 1:5000
Interpretation and polygon delineation of habitats performed at scales from 1:2000 to 1:5000.
2011
Vector
GT-polygon composed of chains
409
WGS 1984 UTM Zone 11N
0.9996
-117.0
0.0
500000.0
0.0
coordinate pair
0.000000002220024164500956
0.000000002220024164500956
Meter
D WGS 1984
WGS 1984
6378137.0
298.257223563
Habitat_OffshoreVentura
Polygons representing habitat map units
This report
OBJECTID
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
Shape
Feature geometry.
ESRI
Coordinates defining the features.
Hab_Code
Habitat code
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 20
Hab_Type
Habitat type
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 50
Mega_ID
Megahabitat ID code
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 10
Mega
Megahabitat description
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 35
Ind_ID
Seafloor induration ID code
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 15
Ind
Seafloor induration description
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 35
Sed_ID
Sediment ID code
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 15
Sed
Sediment description
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 35
Mes_Mac_ID
Meso/Macro-habitat ID code
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 35
Mes_Mac
Meso/Macro-habitat description
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 50
Mod_ID
Habitat modifier ID code
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 35
Mod
Habitat modifier description
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 50
Slope_ID
Slope modifier ID code
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 5
Slope
Slope description
Center for Habitat Studies, Greene and others (1999, 2007)
Names are in text form, maximum length: 35
Area_m
Polygon area in meters
ESRI Calculate Geometry (Area in square meters) tool
97.239197
4185460
Float values in square meters
20120710
Center for Habitat Studies, Moss Landing Marine Laboratories
Charlie Endris
Geologist/GIS Analyst
mailing and physical address
8272 Moss Landing Rd.
Center for Habitat Studies, Moss Landing Marine Laboratories
Moss Landing
CA
95039
US
831-771-4141
831-633-7264
cendris@mlml.calstate.edu
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998