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 https://doi.org/10.3133/ofr20181023

Suggested Citation: Dartnell, P., 2018, Data integration and visualization, Offshore of Gaviota map area, California, sheet 4 in Johnson, S.Y., Dartnell, 

P., Cochrane, G.R., Hartwell, S.R., Golden, N.E., Kvitek, R.G., and Davenport, C.W. (S.Y. Johnson and S.A. Cochran, eds.), California State Waters Map 

Series—Offshore of Gaviota, California: U.S. Geological Survey Open-File Report 2018–1023, pamphlet 41 p., 9 sheets, scale 1:24,000, 

https://doi.org/10.3133/ofr20181023.

ISSN 2331-1258 (online)

https://doi.org/10.3133/ofr20181023

120°30' 120° 119°30'

34°

34°30'

Limit of California’s

State Waters

Kilometers 0 5 10

Santa Barbara Channel

Area of

Map

Santa Barbara CALIF.

MAP LOCATION

Anacapa Is.

Santa Cruz Is.

Santa Rosa Is.

San Miguel Is.

0

80

60

40

20

140

120

160

100

180

DISCUSSION

Mapping California’s State Waters has produced a vast amount of acoustic and visual 

data, including bathymetry, acoustic backscatter, seismic-reflection profiles, and seafloor video 

and photography. These data are used by researchers to develop maps, reports, and other tools 

to assist in the coastal and marine spatial-planning capability of coastal-zone managers and 

other stakeholders. Seafloor-character, habitat, and geologic maps may be used for fisheries 

management, for designation of Marine Protected Areas, for monitoring of environmental 

change such as sea-level-rise impacts, for prediction of sediment and contaminant budgets and 

transport, and for assessment of earthquake and tsunami hazards. To achieve these goals, it is 

helpful to integrate the different datasets and then view the results in three-dimensional 

representations such as those displayed on this data integration and visualization sheet for the 

Offshore of Gaviota map area.

The map view in the center of the sheet is similar to the colored shaded-relief bathymetry 

map of the Offshore of Gaviota map area (see sheet 1 of this report). Numbered arrows show 

viewing directions of the perspective views on this sheet (figs. 1, 2, 4, 5, 6); the numbers 

indicate the figure number of the perspective view.

The perspective views in figures 1, 2, 4, 5, and 6 show the colored shaded-relief bathymetry of the Offshore of Gaviota map area, as viewed from different directions. These views 

highlight the seafloor morphology in the offshore of Gaviota map area, which includes asphalt 

mounds, rock outcrops, gullies, sediment mass-flow deposits, and linear striations interpreted 

as trawling scars.

Video-mosaic images created from digital seafloor video (fig. 3) can display the geologic 

(rock, sand, mud) and biologic complexity of the seafloor. Whereas photographs capture 

high-quality snapshots of smaller areas of the seafloor, video mosaics can capture larger areas 

and, thus, can show transitional zones between different seafloor environments.

Draping the acoustic-backscatter imagery (see sheet 3 of this report) over the bathymetry 

data (fig. 6) highlights the relations between the backscatter intensity and the seafloor 

morphology. It also aids in seafloor habitat and geology interpretations and mapping 

sediment-transport pathways.

Block diagrams (fig. 1), which combine the bathymetry with seismic-reflection-profile 

data (see sheet 7 of this report), help reveal the stratigraphic and structural relations between 

the surface and subsurface.

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]

Data Integration and Visualization, Offshore of Gaviota Map Area, California

By

Peter Dartnell

2018

Perspective views by Peter Dartnell, 2016. Seismic-reflection profile in figure 1 from sheet 7, this report. Video-mosaic image in 

figure 3 by Peter Dartnell, 2015, using software developed by Dr. Yuri Rzhanov, Center for Coastal and Ocean Mapping, University 

of New Hampshire, through joint U.S. Geological Survey–University of New Hampshire cooperative agreement. Acousticbackscatter imagery in figure 6 from map on sheet 3, this report 

GIS database and digital cartography by Nadine E. Golden and Stephen R. Hartwell

Manuscript approved for publication February 12, 2018

Onshore elevation data from National Oceanic and Atmospheric Administration (NOAA) 

Office for Coastal Management's Digital Coast (available at 

http://www.csc.noaa.gov/digitalcoast/data/coastallidar/) and from U.S. Geological Survey’s 

National Elevation Dataset (available at http://ned.usgs.gov/). Offshore shaded-relief 

bathymetry from map on sheet 1, this report

Universal Transverse Mercator projection, Zone 10N

NOT INTENDED FOR NAVIGATIONAL USE

Map view. Colored shaded-relief bathymetry map of 

Offshore of Gaviota map area, generated from 

multibeam-echosounder and bathymetric-sidescan 

data. Colors show depth: reds and oranges indicate 

shallower areas; greens, blueish-greens, and purples 

(in submarine canyons), deeper areas. Illumination 

azimuth is 300°, from 45° above horizon. Ripple 

patterns and parallel lines that are apparent within 

map area are data-collection and -processing 

artifacts; these artifacts are made obvious by 

hillshading process. Numbered arrows show viewing 

directions of perspective views shown on this sheet; 

numbers correspond to figure numbers of views.

Figure 3. Video mosaic generated from seafloor video 

captured over asphalt mound in midshelf area on south 

flank of Gaviota sediment bar (see fig. 2 for location). 

Fresh asphalt apparently is only exposed at very top of 

mound, and outer parts of mound are covered by 

sediment. Camera-sled tow direction is from bottom to 

top; width of mosaic changes because field of view of 

camera changes as camera sled raises and lowers 

relative to seafloor. Green dots are lasers on camera 

sled used to scale features on seafloor. Video mosaic 

created using software developed by Dr. Yuri Rzhanov, 

Center for Coastal and Ocean Mapping, University of 

New Hampshire, through joint U.S. Geological 

Survey–University of New Hampshire cooperative 

agreement.

~ 80 cm

sediment

sediment

kelp

fresh asphalt

Figure 6. Perspective views to northwest across shelf southwest of Gaviota State Park, showing colored shaded-relief bathymetry (A) and acoustic-backscatter imagery (B). In 

acoustic-backscatter imagery, lighter tones indicate stronger backscatter intensity, suggesting rock or coarser grained sediment, whereas darker tones indicate weaker backscatter 

intensity, suggesting finer grained sediment. Views show outcrop (SF) of the upper Miocene and lower Pliocene Sisquoc Formation (see sheet 9 of this report), exposed near left side of 

image. Northeast (to right) of outcrop, northeast-trending linear striations (ts) on midshelf are interpreted as trawling scars (see sheet 9). Backscatter imagery (B) shows that striations have 

higher backscatter intensity than surrounding seafloor. North-south-trending, short black lines in bathymetry imagery and east-west-trending, straight, light-colored lines in backscatter 

imagery are all data-collection and -processing artifacts. Vertical exaggeration of perspective views, 2x; distance across bottom of both views, about 1.9 km.

A

B

SF

SF

ts

ts

Figure 5. Perspective view to northeast over nearshore area east of Point Conception, showing differentially eroded, fractured, and folded bedrock of the upper Miocene 

and lower Pliocene Sisquoc Formation (see sheet 9 of this report), which dominates nearshore area. Fault near bottom of view (e; see also, sheet 9) offsets distinctive 

linear strata by as much as 60 m. Linear feature (f) crossing nearly perpendicular to distinctive linear strata is possible undersea cable or pipeline. White line and 

converging arrows show axis of Government Point Syncline. Sediment-filled channel (ch) cuts through outcrop. Vertical exaggeration, 2x; distance across bottom of 

image, about 1.8 km. 

e

f

ch

Figure 4. Perspective view to northwest offshore of Gaviota State Park, showing mass-flow deposits (m) on south flank of Gaviota sediment bar, which dips as steeply 

as 5°, whereas shelf (s) dips about 1.0° to 1.2° offshore. Mass-flow deposits locally extend across shelf break (sb) to upper slope (us); asphalt deposits (d) (see figs. 2, 

3) are found within mass-flow deposits. Also shown is “Alegria Canyon” (ac). Vertical exaggeration, 2x; distance across of image, about 7 km. 

 Gaviota 

State Park

m

Gaviota sediment bar

s

us

sb

d

ac

Figure 2. Perspective view to north over outer shelf southwest of Gaviota State Park, showing field of asphalt mounds (c) along south flank of Gaviota sediment bar 

and across “Alegria Canyon” (ac). Mounds are as much as 40 m wide and have as much as 2 m of vertical relief above surrounding seafloor. Thin white line shows 

path of camera sled, towed 1 to 2 m over seafloor, that captured video and photographs. White rectangle shows location of video mosaic (fig. 3) generated from 

video captured over an asphalt deposit. Parallel lines in bathymetry are data-collection and -processing artifacts. Vertical exaggeration, 2x; distance across bottom 

of image, about 1.8 km. 

c

Gaviota sediment bar

ac

A

B

Figure 1. Perspective views to east over area south of Gaviota State Park. A, Perspective view of Gaviota sediment bar, shelf (s), shelf break (sb), and upper slope 

(us), showing larger (a) and smaller (b) canyons, gullies, and rills cutting into midshelf, outer shelf, and upper slope areas. Larger canyons such as “Alegria 

Canyon” (ac) propagate farther upslope, cutting through shelf and slope and into Gaviota sediment bar. Black line shows location of seismic-reflection profile in 

B below. B, Same perspective view as A, converted to block diagram that combines bathymetry with north-south-trending seismic-reflection profile GS–70 (also 

shown in fig. 5 on sheet 7 of this report, as viewed from opposite direction and at reduced vertical exaggeration). Block diagram shows that larger gullies are 

cutting through uppermost Pleistocene and Holocene sediments on shelf (blue shading). Mass-flow deposits are found on both south flank of Gaviota sediment 

bar and on steep upper slope (purple shading) (see fig. 4 for different view of mass-flow deposits; see also, sheets 7, 9 of this report). Dashed yellow line shows 

seafloor multiple (echo of seafloor reflector). Vertical exaggeration in both views, 2x; distance across bottoms, about 1.4 km.

a

a

b

b

Gaviota sediment bar

s

us

sb

Gaviota sediment bar

ac

a b

s

us

sb

ac

5

2

6

1

4

 Gaviota 

State Park

2 km

Open-File Report 2018–1023

Sheet 4 of 9

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey