This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of Half Moon Bay map area, California.
The polygon shapefile is included in "Habitat_OffshoreHalfMoonBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreHalfMoonBay/data_catalog_OffshoreHalfMoonBay.html.
Using multibeam echosounder (MBES) bathymetry and backscatter data (see Bathymetry; Backscatter A [8101]; and Backscatter
B [7125]--Offshore Half Moon Bay, California, DS 781), 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.
Citation
Title Habitat--Offshore of Half Moon Bay, California
publication Date
2013-01-01
presentationForm
POLYGON SHAPEFILE DIGITAL DATA
cited responsible party
-
originator
organisation Name
B. Dieter
cited responsible party
-
originator
organisation Name
H.G. Greene
cited responsible party
-
originator
organisation Name
C.A. Endris
cited responsible party
-
originator
organisation Name
Center for Habitat Studies, Moss Landing Marine Laboratories
other Citation Details
Cinergi keyword enhanced at Sun Nov 13 18:30:34 UTC 2016
purpose:
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 along the coast of central California. This information is not intended
for navigational purposes.
Use Constraints: 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.
Constraints on resource usage:
Legal Constraints
Access Constraints
otherRestrictions
Other constraints
Access Constraints: 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
Spatial representation type code:
vector
Processing environment:
Native Dataset Environment: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcGIS 10.0.3.3600
Resource extent
Geographic Extent
Geographic Bounding Box
westBoundLongitude
-122.59
eastBoundLongitude
-122.42
northBoundLatitude
37.55
southBoundLatitude
37.39
Temporal Extent
2013-01-01
Additional information on resource:
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.10.0. 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 offshore Half Moon Bay. 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.
point of contact
-
pointOfContact
individual Name H. Gary Greene
organisation Name
Center for Habitat Studies, Moss Landing Marine Laboratories
position Name Geologist/Principal Investigator
Contact information
Telephone
Voice (831) 771-4141
Fax (831) 633-7264
Address
Center for Habitat Studies, Moss Landing Marine Labs, CA, 95039
Country USA
name Of Measure Horizontal Positional Accuracy Report
evaluation Method Description
Interpretation and polygon delineation of habitats performed at scales from 1:2000 to 1:5000
Completeness Commission
evaluation Method Description
Contact authors for information about omissions, selection criteria, generalization, definitions used, and other rules used
to derive the data set.
Completeness Omission
evaluation Method Description
Contact authors for information about omissions, selection criteria, generalization, definitions used, and other rules used
to derive the data set.
ConceptualConsistency
measure Description
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.
notes: This metadata was automatically generated from the FGDC Content Standard for Digital Geospatial Metadata standard (version
FGDC-STD-001-1998) using the 2012-06-20T17:21:00 version of the FGDC RSE to ISO 19115-2 transform.
notes: Last Metadata Review Date: 2014-08-26
Metadata contact
-
pointOfContact
individual Name Charlie Endris
organisation Name
Center for Habitat Studies, Moss Landing Marine Laboratories
position Name Geologist/GIS Analyst
Contact information
Telephone
Voice 831-771-4141
Fax 831-633-7264
Address
8272 Moss Landing Rd.Center for Habitat Studies, Moss Landing Marine Laboratories, Moss Landing, CA, 95039
Country US