California State Waters Map Series: Offshore of Santa Barbara, California
<p>In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map…
Public-domain full text preserved in the Mountain Man Mining Library. Original source: pubs.usgs.gov.
Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters and between X and Y directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and proportions may not be true on plots of this map. For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1–888–ASK–USGS Digital files available at ://pubs.usgs.gov/sim/3281/ Suggested Citation: Kvitek, R.G., Dartnell, P., Phillips, E.L., and Cochrane, G.R., 2013, Colored shaded-relief bathymetry, Offshore of Santa Barbara map area, California, sheet 1 in Johnson, S.Y., Dartnell, P., Cochrane, G.R., Golden, N.E., Phillips, E.L., Ritchie, A.C., Greene, H.G., Krigsman, L.M., Kvitek, R.G., Dieter, B.E., Endris, C.A., Seitz, G.G., Sliter, R.W., Erdey, M.D., Gutierrez, C.I., Wong, F.L., Yoklavich, M.M., Draut, A.E., Hart, P.E., and Conrad, J.E. (S.Y. Johnson and S.A. Cochran, eds.), California State Waters Map Series—Offshore of Santa Barbara, California: U.S. Geological Survey Scientific Investigations Map 3281, pamphlet 45 p., 11 sheets, scale 1:24,000, ://dx.doi.org/10.3133/sim3281. ISSN 2329-132X (online) ://dx.doi.org/10.3133/sim3281 US Army Corps of Engineers Figure 1. Map showing areas of multibeam-echosounder and bathymetric-sidescan surveys (pink shading), bathymetric- and topographic-lidar surveys (orange diagonal lines), and publicly available interferometric synthetic aperture radar (ifSAR) topography (yellow shading). Also shown are data-collecting agencies (CSUMB, California State University, Monterey Bay, Seafloor Mapping Lab; USACE, U.S. Army Corps of Engineers; USGS, U.S. Geological Survey) and dates of surveys if known. Santa Barbara USGS, 2006 USGS, USGS, 2006 CSUMB, 2007 119°45' 119°40' 34°25' 34°20' USACE, 2009 DISCUSSION This colored shaded-relief bathymetry map of the Offshore of Santa Barbara map area in southern California was generated from bathymetry data collected by California State University, Monterey Bay (CSUMB), by the U.S. Geological Survey (USGS), and by Fugro Pelagos for the U.S. Army Corps of Engineers (USACE) Joint Lidar Bathymetry Technical Center of Expertise (fig. 1). Most of the offshore area was mapped by CSUMB in the summer of 2007, using a 244-kHz Reson 8101 multibeam echosounder. Smaller areas in the far-east nearshore, as well as further offshore to the west and in the southeast outer shelf area, were mapped by the USGS in 2005 and 2006, using a combination of 468-kHz (2005) and 117-kHz (2006) SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonars. The nearshore bathymetry and coastal topography were mapped for USACE by Fugro Pelagos in 2009, using the SHOALS-1000T bathymetric-lidar and Leica ALS60 topographic-lidar systems. These mapping missions combined to collect bathymetry from the 0-m isobath to beyond the 3-nautical-mile limit of California’s State Waters. During the CSUMB mapping mission, an Applanix position and motion compensation system (POS/MV) was used to accurately position the vessel during data collection, and it also accounted for vessel motion such as heave, pitch, and roll (position accuracy, ±2 m; pitch, roll, and heading accuracy, ±0.02°; heave accuracy, ±5%, or 5 cm). NavCom 2050 GPS receiver (CNAV) data were used to account for tidal-cycle fluctuations, and sound-velocity profiles were collected with an Applied Microsystems (AM) SVPlus sound velocimeter. Soundings were corrected for vessel motion using the Applanix POS/MV data, for variations in water-column sound velocity using the AM SVPlus data, and for variations in water height (tides) using vertical-position data from the CNAV receiver. During the USGS mapping missions, differential GPS (DGPS) data were combined with measurements of vessel motion (heave, pitch, and roll) in a CodaOctopus F180 attitude-and-position system to produce a high-precision vessel-attitude packet. This packet was transmitted to the acquisition software in real time and combined with instantaneous sound-velocity measurements at the transducer head before each ping. The returned samples were projected to the seafloor using a ray-tracing algorithm that works with previously measured sound-velocity profiles. Statistical filters were applied to the raw samples that discriminate the seafloor returns (soundings) from unintended targets in the water column. Finally, the soundings were converted into 2-m-resolution bathymetric-surface-model grids. During the Fugro Pelagos mapping mission that was completed as part of the National Coastal Mapping Program of USACE, the Leica ALS60 topographic-lidar and the SHOALS-1000T bathymetric-lidar systems were mounted on an aircraft that flew survey lines at an altitude of 300 to 400 m (bathymetry) and 300 to 1,200 m (topography), at speeds of between 135 and 185 knots. The ALS60 system collected data at a maximum pulse rate of 200 kHz, and the SHOALS system collected data at 1 kHz. Information on aircraft position, velocity, and acceleration were collected using the Novatel and POS A/V 410 systems (SHOALS) and the onboard GPS/IMU system (ALS60). Aircraft-position data were processed using POSPac software, and the results were combined with the lidar data to produce 3-D positions for each lidar shot. Various commercial and proprietary software packages were used to clean the data, to convert all valid data from ellipsoid to orthometric heights, and to export the data as a series of topography and bathymetry ASCII files. Soundings from the different mapping missions were converted into individual 2-m-resolution bathymetric-surface-model grids. The individual bathymetric-surface models were then merged into one overall bathymetric-surface model and clipped to the boundary of the map area. An illumination having an azimuth of 300° and from 45° above the horizon was then applied to the bathymetric surface to create the shaded-relief imagery. In addition, a modified “rainbow” color ramp was applied to the bathymetry data, using reds and oranges to represent shallower depths, and greens to represent greater depths (note that the Offshore of Santa Barbara map area requires only the shallower part of the full-rainbow color ramp used on some of the other maps in the California State Waters Map Series; see, for example, Kvitek and others, 2012). This colored bathymetry surface was draped over the shaded-relief imagery at 60-percent transparency to create this colored shaded-relief map. Bathymetric contours were generated from a modified 10-m-resolution bathymetric surface where a smooth arithmetic mean convolution function that assigns a weight of one-ninth to each cell in a 3-pixel by 3-pixel matrix was applied iteratively to the surface ten times. The onshore-area image was generated by applying the same illumination (azimuth of 300° and from 45° above the horizon) to the coastal airborne topographic-lidar data, as well as to publicly available, 3-m-resolution, interferometric synthetic aperture radar (ifSAR) data, available from National Oceanic and Atmospheric Administration (NOAA) Coastal Service Center’s Digital Coast, at ://csc-s-maps-q.csc.noaa.gov/ dataviewer/viewer. (last accessed April 5, 2011). REFERENCE CITED Kvitek, R.G., Phillips, E.L., and Dartnell, P., 2012, Colored shaded-relief bathymetry, Hueneme Canyon and vicinity, California, sheet 1 in Johnson, S.Y., Dartnell, P., Cochrane, G.R., Golden, N.E., Phillips, E.L., Ritchie, A.C., Kvitek, R.G., Greene, H.G., Krigsman, L.M., Endris, C.A., Clahan, K.B., Sliter, R.W., Wong, F.L., Yoklavich, M.M., and Normark, W.R. (S.Y. Johnson, ed.), California State Waters Map Series—Hueneme Canyon and vicinity, California: U.S. Geological Survey Scientific Investigations Map 3225, pamphlet 41 p., 12 sheets, available at ://pubs.usgs.gov/sim/3225/. EXPLANATION Depth (in meters) and illumination (bright areas are illuminated, facing false sun; dark areas are in shadow, facing away from false sun) Shallow Deep Direction of illumination from false sun—Position of false sun is at 300° azimuth, 45° above horizon [arrow included in explanation for illustration purposes only; not shown on map] Area of “no data”—Areas near shoreline not mapped owing to insufficient high-resolution seafloor mapping data; areas beyond 3-nautical-mile limit of California’s State Waters were not mapped as part of California Seafloor Mapping Program 3-nautical-mile limit of California’s State Waters Bathymetric contour (in meters)—Derived from modified 10-m-resolution bathymetry grid. Contour interval: 10 m CALIF. 8 Nautical Miles Kilometers 120° 119°40' 119°20' 119° 34° 34°20' MAP LOCATION Ventura Santa Barbara Anacapa Island Santa Cruz Island Santa Rosa Island Area of Map Santa Barbara Channel Limit of California’s State Waters 1California State University, Monterey Bay, Seafloor Mapping Lab; 2U.S. Geological Survey Colored Shaded-Relief Bathymetry, Offshore of Santa Barbara Map Area, California By Rikk G. Kvitek,1 Peter Dartnell,2 Eleyne L. Phillips,2 and Guy R. Cochrane2 ONE MILE 0.869 NAUTICAL MILES BATHYMETRIC CONTOUR INTERVAL 10 METERS 1 KILOMETER 7000 FEET 1/2 1 MILE SCALE 1:24 000 APPROXIMATE MEAN DECLINATION, 2013 MAGNETIC NORTH 12 / ° TRUE NORTH Shaded-relief bathymetry by Peter Dartnell, 2012 (data collected by U.S. Geological Survey in 2005 and 2006, by California State University, Monterey Bay, Seafloor Mapping Lab in 2007, and by U.S. Army Corps of Engineers in 2009). Bathymetric contours by Andrew C. Ritchie, 2011 GIS database and digital cartography by Nadine E. Golden and Eleyne L. Phillips Edited by Taryn A. Lindquist Manuscript approved for publication December 12, 2013 Onshore elevation data from NOAA Coastal Services Center (data collected by EarthData International in 2002-2003) and from U.S. Army Corps of Engineers (data collected by Fugro Pelagos in 2009). California's State Waters limit from NOAA Office of Coast Survey Universal Transverse Mercator projection, Zone 11N NOT INTENDED FOR NAVIGATIONAL USE Santa Barbara 119°45' 119°40' 34°25' 34°20' 119°45' 119°40' 34°25' 34°20' Scientific Investigations Map 3281 Sheet 1 of 11 Pamphlet accompanies map U.S. Department of the Interior U.S. Geological Survey