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 http://dx.doi.org/10.3133/ofr20151232

Suggested Citation: Dartnell, P., 2015, Data integration and visualization, Offshore of Pigeon Point map area, California, sheet 4 in 

Cochrane, G.R., Watt, J.T., Dartnell, P., Greene, H.G., Erdey, M.D., Dieter, B.E., Golden, N.E., Johnson, S.Y., Endris, C.A., Hartwell, S.R., 

Kvitek, R.G., Davenport, C.W., Krigsman, L.M., Ritchie, A.C., Sliter, R.W., Finlayson, D.P., and Maier, K.L. (G.R. Cochrane and S.A. 

Cochran, eds.), California State Waters Map Series—Offshore of Pigeon Point, California: U.S. Geological Survey Open-File Report 

2015–1232, pamphlet 40 p., 10 sheets, scale 1:24,000, http://dx.doi.org/10.3133/ofr20151232.

ISSN 2331-1258 (online) 

http://dx.doi.org/10.3133/ofr20151232

37°

36°40'

122°20' 122°

Santa Cruz

Monterey

Moss 

Landing

Pigeon

Point

Limit of California’s

State Waters

Area of

Map

CALIF.

MAP LOCATION

0 5 10 Kilometers

0 5 10Nautical Miles

121°40'

Monterey

Bay

20

30

40

50

60

70

10

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 Pigeon Point map area. 

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

map of the Offshore of Pigeon Point map area (see sheet 1 of this report). Numbered arrows 

show viewing directions of the perspective views on this sheet; the numbers indicate the figure 

number of the perspective view.

The perspective views and bathymetric profiles in figures 1, 2, 4, 5, and 6 show the 

colored shaded-relief bathymetry of the Offshore of Pigeon Point map area, as viewed from 

different directions. These views highlight the diverse seafloor environments in this map area, 

which include areas of featureless, sedimented seafloor, interspersed with complex distributions of shallow depressions, as well as folded and fractured sedimentary rocks.

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

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

high-quality snapshots of a small area of the seafloor (see sheet 6 of this report), 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. 4) highlights the relations between the backscatter intensity and the seafloor 

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

sediment-transport pathways.

Block diagrams (fig. 5), which combine the bathymetry with seismic-reflection-profile 

data (see sheet 8 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 Pigeon Point Map Area, California

By

Peter Dartnell

2015

Perspective views by Peter Dartnell, 2014. Bathymetric profile in figure 2 by Peter Dartnell, 2014. Video-mosaic image in figure 3 

by Peter Dartnell, 2014, 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. Acoustic-backscatter 

imagery in figure 4 from map on sheet 3, this report. Seismic-reflection profile in figure 6 from sheet 8, this report

GIS database and digital cartography by Nadine E. Golden

Manuscript approved for publication December 4, 2015

Onshore elevation data from California Coastal Conservancy (available 

from National Oceanic and Atmospheric Administration [NOAA] Coastal 

Service Center’s Digital Coast 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/). California's State Waters limit 

from NOAA Office of Coast Survey

Universal Transverse Mercator projection, Zone 10N

NOT INTENDED FOR NAVIGATIONAL USE

 Pigeon Point

 Año Nuevo

 State Park

 Año Nuevo

 Island

2

4

6

1

Map view. Colored shaded-relief bathymetry map of 5

Offshore of Pigeon Point map area, generated from 

multibeam-echosounder and bathymetric-sidescan 

data. Colors show depth: reds indicate shallower 

areas; yellows, 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. Lines at 

borders of some surveys result from slight 

differences in depth, as measured by different 

mapping systems in different years. These various 

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. 

Franklin

 Point

Figure 1. Perspective view to north along San Mateo County coast past Año Nuevo State Park and Island. View highlights extensive layered and fractured bedrock of the 

middle and upper Miocene Monterey Formation (see sheets 8 and 10 of this report) with featureless seafloor offshore. Thin yellow line shows path of camera sled, towed 1 

to 2 m above seafloor, that captured video and photographs; yellow arrow shows tow direction. Yellow rectangle shows location of video mosaic (fig. 3) generated from 

video captured over the transition from featureless seafloor to rock outcrop. Vertical exaggeration, 2x; distance across bottom of image, about 1.7 km.

Figure 2. Perspective view to southeast over area offshore of Año Nuevo State Park and bathymetric profile A–A'. Moderate-relief rock outcrop is exposed on seafloor 

directly offshore (a) as well as farther offshore surrounding Año Nuevo Island (b). In between outcrops (a, b) is smooth, featureless seafloor (c), likely composed of sand. 

Profile A–A' reveals field of sand in nearshore that is at same depth or shallower than outcrop. Sand, likely transported down coast, covers outcrop and may also 

contribute to sand dunes onshore in Año Nuevo State Park. Vertical exaggeration of perspective view, 2x; distance across bottom of image, about 1.3 km, vertical 

exaggeration of profile A–A', about 20x.

A A’

A’

A

Distance (m)

50 100 150 200 250 300

Depth (m) 8.0

7.6

8.4

0

Figure 4. Perspective views to northeast over nearshore area offshore of Pigeon Point, 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. Colored shaded-relief bathymetry shows complex distribution of low-relief scour depressions (d) and rock outcrop in 

nearshore (e). Acoustic-backscatter imagery reveals that shallow depressions contain very high backscatter intensities suggesting depressions are filled with coarser grained 

sands and gravels. Backscatter intensities of scour depressions are similar to nearshore rock outcrop. Parallel lines of higher backscatter in (B) are data-collection and -processing 

artifacts. Vertical exaggeration of perspective views, 2x; distance across bottom of both views, about 1.3 km. 

A

B

 Año Nuevo

 State Park

 Año Nuevo

 Island

 Año Nuevo

 State Park Año Nuevo

 Island

 Pigeon Point

 Pigeon Point

 backscatter data gap

Figure 5. Perspective views to northwest over area offshore of Año Nuevo State Park and Año Nuevo Island. A, Perspective view of seafloor near Año Nuevo Island showing extensive rock 

outcrop surrounding island and low-relief seafloor offshore. Ripple patterns and parallel lines are data-collection artifacts. Black line shows location of seismic-reflection profile in B. B, 

Same perspective view as A, converted to block diagram that combines bathymetry with east-west-trending seismic-refection profile MBS–33 (also shown in fig. 9 on sheet 8 of this 

report). Blue shading shows inferred uppermost Pleistocene and Holocene strata. Dashed red lines show faults. Dashed blue line shows unconformity. Dashed green lines highlight some 

continuous reflectors that reveal structure (not distinctive stratigraphic markers). Dashed yellow line is seafloor multiple (echo of the seafloor reflector). Vertical exaggeration of 

perspective views, 2x; distance across bottom of perspective view A, about 4.5 km; depth of base of seismic-reflection profile in B, about 180 m.

 Año Nuevo 

 State Park

 Año Nuevo 

 Island

 Año Nuevo 

 State Park

 Año Nuevo 

 Island

A

B

Franklin

 Point

Figure 6. Perspective view to east over nearshore area offshore of Franklin Point, showing rock outcrop in nearshore and featureless seafloor offshore. Outcrop mapped 

as Upper Cretaceous Pigeon Point Formation, which consists of sandstone and conglomerate, interbedded with siltstone and mudstone (see sheet 10 of this report). To 

north and south, outcrop has as much as 6 m of seafloor relief. In center of perspective view, outcrop has less than 2 m of relief and is mainly covered by upper Holocene 

shelf deposits. Rock burial rates likely fluctuate from season to season along this energetic stretch of coast. Vertical exaggeration, 2x; distance across bottom of image, 

about 2.5 km.

a

b

c

d

d

e

e

d

d

e

e

160

80

Approx Depth (m)

transition from sandy

seafloor with small 

ripples to layered 

sedimentary bedrock

layered sedimentary

bedrock

sand

camera 

sled 

paired 

lasers

Figure 3. Video mosaic of area offshore of Año Nuevo Island (see fig. 1 for 

location), revealing transition from sandy seafloor to rock outcrop. Outcrop is 

composed of layered sedimentary bedrock that is relatively clean of encrusting 

organisms, algae, and kelp. Image shows linear ridges of rock, perpendicular to 

path of camera sled, that are consistent with seafloor morphology shown in 

figure 1. Camera-sled tow direction is from bottom to top. Green and red dots 

within mosaic are from paired lasers on camera sled, used to determine scale of 

objects on seafloor. Mosaic made up of about 1 minute of video as camera sled 

traveled over 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.

~140 cm (55 in)

Open-File Report 2015–1232

Sheet 4 of 10

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey