Guy R. Cochrane
2015
Seafloor character from sidescan sonar data-Santa Barbara Channel
1.0
GeoTIFF
data release
DOI:10.5066/F7QF8QXF
Pacific Coastal and Marine Science Center, Santa Cruz, California
U.S. Geological Survey, Coastal and Marine Geology Program
https://doi.org/10.5066/F7QF8QXF
https://www.sciencebase.gov/catalog/file/get/55c9162de4b08400b1fd88c5
Guy R. Cochrane
2015
Data Release for Santa Barbara Channel Regional Importance of Manmade Structures as Rockfish Nurseries Study
document
Data Release
doi:10.5066/F7QF8QXF
Pacific Coastal and Marine Science Center, Santa Cruz, California
U.S. Geological Survey, Coastal and Marine Geology Program
https://doi.org/10.5066/F7QF8QXF
Substrate was classified using the method of (Cochrane and Lafferty, 2002) for this study. Sea floor character derived from towed sidescan sonar data is available for the mainland coast within the study area from USGS online publications (Cochrane and others, 2003; Cochrane and others, 2005). The number of substrate classes was reduced because rugosity could not be derived for all areas due to the lack of bathymetry data for other data sets used in the study.
References Cited:
Cochrane, G.R., Nasby, N.M., Reid, J.A., Waltenberger, B., Lee, K.M., 2003, Nearshore Benthic Habitat GIS for the Channel Islands National Marine Sanctuary and Southern California State Fisheries Reserves Volume 1: U.S. Geological Survey Open-File Report 03-85, http://pubs.usgs.gov/of/2003/0085/.
Cochrane, G.R., and Lafferty, K.D., 2002, Use of acoustic classification of sidescan sonar data for mapping benthic habitat in the Northern Channel Islands, California: Continental Shelf Research, v. 22, p. 683-690.
Cochrane, G.R., Conrad, J.E., Reid, J.A., Fangman, S., Golden, N.E., 2005, The Nearshore Benthic Habitat GIS for the Channel Islands National Marine Sanctuary and Southern California State Fisheries Reserves, Volume II; Version 1.0: U.S. Geological Survey Open-File Report 2005-1170, http://pubs.usgs.gov/of/2005/1170/.
These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify local seafloor character.
2002
2004
ground condition
As needed
-119.674
-119.331
34.084
33.960
USGS Metadata Identifier
USGS:d1129bd8-83bf-4362-8442-aed21e132b51
Global Change Master Directory (GCMD)
Biosphere > Aquatic Ecosystems > Benthic Habitat
Biosphere > Aquatic Ecosystems > Marine Habitat
ISO 19115 Topic Category
geoscientificInformation
environment
oceans
imageryBaseMapsEarthCover
USGS Thesaurus
benthic ecosystems
sidescan sonar
Marine Realms Information Bank (MRIB) keywords
sidescan sonar
benthos
Data Categories for Marine Planning
Physical Habitats and Geomorphology
None
U.S. Geological Survey
USGS
Pacific Coastal and Marine Science Center
PCMSC
Coastal and Marine Geology Program
CMGP
Geographic Names Information System (GNIS)
Pacific Ocean
State of California
Santa Barbara Channel
Channel Islands
None
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigation purposes.
Guy R. Cochrane
U.S. Geological Survey,
Pacific Coastal and Marine Science Center
Geophysicist
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060-5792
USA
(831)460-7554
(831)427-4709
gcochrane@usgs.gov
https://www.sciencebase.gov/catalog/item/imap/55c9162de4b08400b1fd88c5
Seafloor character types Santa Barbara Channel and Northern Channel Islands.
map service
Pixel resolution 2 m.
Classification was done on the basis of training samples delineated by interpreter. The classification was performed using mathematical algorithms then hand-edited by the interpreter to remove noise.
Survey area is defined by coverage of sidescan backscatter datasets.
Positional information reflects the position of the ship and was collected using a WAAS-enabled GSP unit, recording at between 1 to 2 nm. DGPS (WAAS) accuracy for position is less than 3 meters. (From Garmin GPSMAP 76C/76CS Specifications, M01-10108-00, Rev0304, <https://http://www8.garmin.com/specs/GPSMAP76C_76CSspec.pdf>). Towed sidescan distance from ship is variable depending on water depth and layback distance between the gps unit and the stern. Accuracy is on the order of 100 meters.
The seafloor-character map was produced using video-supervised maximum likelihood classification of and intensity of return from sidescan sonar and textural indices derived from the backscatter data. 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 (2002). The two variants used in this classification were homogeneity and . Both mimic terrain ruggedness using the variation in intensity of grid cells within a neighborhood. This method effectively captures variability into a single measure.
Classes I, II and III values were delineated using maximum likelihood analysis. 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.
2011
The sea floor character rasters were reclassed combining classes II and III. The blocked rasters were mosaicked into a single raster.
2011
Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.
20201019
U.S. Geological Survey
VeeAnn A. Cross
Marine Geologist
Mailing and Physical
384 Woods Hole Road
Woods Hole
MA
02543-1598
508-548-8700 x2251
508-457-2310
vatnipp@usgs.gov
Raster
Pixel
7465
16191
1
WGS 1984 UTM 11N
0.9996
-117
0.0
500000
0.0
coordinate pair
0.0001
0.0001
Meter
D WGS 1984
WGS 1984
6378137.0
298.257223563
ss_sfc.tif.vat
The attributes include VALUE - code for the seafloor character classes, COUNT - number of pixels. The raster can be added to any ESRI ArcMap project.
ESRI
OID
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
VALUE
This seafloor-character class was produced using video-supervised maximum-likelihood classification of sidescan sonar backscatter (intensity of return). Derivative homogeneity, entropy, and backscatter intensity were used as variants in the classification. In order to combine the results with results for areas that had no rugosity information this data set was reduce to a simple hard versus sogt bottom classification. A value of 1 indicates deposits of mud and sand thick enough to support infauna. A value of 2 indicates hard bottom including gravel, cobble, boulder, and bedrock.
ESRI
1
2
Integers representing seafloor character classes
COUNT
The number of pixels (2m x 2m size grid cell) represented in each seafloor class (see Attribute: VALUE).
ESRI
1618675
3711996
Integer representing pixel count
U.S. Geological Survey - ScienceBase
Mailing and Physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
1-888-275-8747
sciencebase@usgs.gov
Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
GeoTIFF
ArcMap (version 10.1)
Raster data layer is registered TIFF image in the UTM Zone 11 coordinate system with datum WGS84.
The .zip file for the TIFF image includes the image (.tif), the world registration file (.tfw) and other associated files, FGDC-compliant metadata
Zip
2.5
https://www.sciencebase.gov/catalog/file/get/55c9162de4b08400b1fd88c5
https://doi.org/10.5066/F7QF8QXF
Data can be downloaded via the World Wide Web (WWW)
none
The downloadable data file has been compressed with the "zip" command and can be unzipped with Winzip (or other tool) on Windows systems. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing an Esri ArcMap TIFF. Users should download the ArcGIS Project File, Air_photoseaflo.zip, a compressed (with the "zip" command) version of the ArcMap document (.mxd) that has all the data layers loaded in the table of contents for “SantaBarbaraChannelGeohab” and has all the data symbolized as on the data release map sheets. Download and save this ArcGIS project file, including all data layers, to the directory the user has created for this GIS.
20201019
Guy R. Cochrane
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Geophysicist
mailing and physical
2885 Mission Street
Santa Cruz
California
95060
USA
(831)460-7554
gcochrane@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998