noaa / NATIONAL OCEANIC AND

ATMOSPHERIC ADMINISTRATION

National Environmental Satellite,

Data, and Information Service

NOAA Technical Memorandum NESDIS NGDC-29

DIGITAL ELEVATION MODEL OF SANTA BARBARA, CALIFORNIA:

PROCEDURES, DATA SOURCES AND ANALYSIS 

K.S. Carignan 

L.A. Taylor

B.W. Eakins

R.R. Warnken

E. Lim

P.R. Medley

National Geophysical Data Center

Marine Geology and Geophysics Division

Boulder, Colorado

March 2009

UNITED STATES

DEPARTMENT OF COMMERCE

Gary Locke

Secretary

NATIONAL OCEANIC AND

ATMOSPHERIC ADMINISTRATION

Dr. Jane Lubchenco

Under Secretary for Oceans

and Atmosphere/Administrator

National Environmental Satellite,

Data, and Information Service

Mary E. Kicza

Assistant Administrator

NOAA Technical Memorandum NESDIS NGDC-29

DIGITAL ELEVATION MODEL OF SANTA BARBARA, CALIFORNIA:

PROCEDURES, DATA SOURCES AND ANALYSIS 

Kelly S. Carignan1 

Lisa A. Taylor2

Barry W. Eakins1

Robin R. Warnken2

Elliot Lim1

Pamela R. Medley1

1

Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder

2

NOAA, National Geophysical Data Center, Boulder, Colorado 

National Geophysical Data Center

Marine Geology and Geophysics Division 

Boulder, Colorado

March 2009
Carignan et al., 2009

ii

NOTICE

Mention	of	a	commercial	company	or	product	does	not	constitute	an	endorsement	by	the	

NOAA National Environmental Satellite, Data, and Information Service.	Use	of	information	

from	this	publication	concerning	proprietary	products	or	the	test	of	such	products	for	publicity

or	advertising	purposes	is	not	authorized.	

Corresponding project contact:

Lisa A. Taylor

NOAA National Geophysical Data Center

Marine Geology and Geophysics Division

325 Broadway, E/GC 3

Boulder, Colorado 80305

Phone: 303-497-6767

Fax: 303-497-6513

E-mail: Lisa.A.Taylor@noaa.gov

http://www.ngdc.noaa.gov/mgg/inundation/tsunami/inundation.html

Also available from the National Technical Information Service (NTIS)

(http://www.ntis.gov)
Digital Elevation Model of Santa Barbara, California

iii

Contents

1.	 Introduction........................................................................................................................................1

2.	 Study Area..........................................................................................................................................2

3.	 Methodology ......................................................................................................................................2

3.1	 Data Sources and Processing ......................................................................................................3

3.1.1	 Shoreline................................................................................................................4

3.1.2	 Bathymetry ............................................................................................................6

3.1.3	 Topography..........................................................................................................15

3.2	 Establishing Common Datums .................................................................................................23

3.2.1	 Vertical datum transformations ...........................................................................23

3.2.2	 Horizontal datum transformations.......................................................................23

3.3	 Digital Elevation Model Development .....................................................................................24

3.3.1	 Verifying consistency between datasets..............................................................24

3.3.2	 Smoothing of bathymetric data ...........................................................................24

3.3.3	 Gridding the data with MB-System......................................................................25

3.4	 Quality Assessment of the DEM...............................................................................................25

3.4.1	 Horizontal accuracy.............................................................................................25

3.4.2	 Vertical accuracy .................................................................................................25

3.4.3	 Slope maps and 3-D perspectives........................................................................26

3.4.4	 Comparison with source data files.......................................................................27

3.4.5	 Comparison with NGS geodetic monuments......................................................28

4.	 Summary and Conclusions...............................................................................................................29

5.	 Acknowledgments............................................................................................................................29

6.	 References........................................................................................................................................29

7.	 Data Processing Software ................................................................................................................30

List of Figures

Figure 1. 	 Shaded-relief image of the Santa Barbara DEM.........................................................................1

Figure 2.	 Overview of Santa Barbara DEM region on NASA World Wind I-cubed image.......................2

Figure 3.	 Source and coverage of datasets used in compiling the Santa Barbara DEM ............................3

Figure 4.	 Digital coastline datasets used in developing a combined coastline of the

	 Santa Barbara region............................................................................................................4

Figure 5.	 2008 aerial photos of Santa Clara River mouth..........................................................................5

Figure 6.	 Spatial coverage of the bathymetric datasets used in compiling the Santa Barbara

	 DEM ....................................................................................................................................7

Figure 7.	 Digital NOS hydrographic survey coverage in the Santa Barbara region ..................................9

Figure 8.	 Spatial coverage of CSUMB multibeam swath sonar surveys used in compiling the Santa

Barbara DEM.....................................................................................................................10

Figure 9.	 Shaded-relief image showing spatial coverage of the 2004 USGS multibeam swath sonar

	 survey.................................................................................................................................11

Figure 10.	 Spatial coverage of USACE multibeam bathymetric surveys used in compiling the Santa

Barbara DEM.....................................................................................................................12

Figure 11.	 Spatial coverage of NGDC multibeam data used in compiling the Santa Barbara

	 DEM ..................................................................................................................................13

Figure 12.	 Detail of section of Channel multibeam bathymetric survey removed from the dataset..........14

Figure 13.	 Spatial coverage of the topographic datasets used in compiling the Santa Barbara

	 DEM ..................................................................................................................................15

Figure 14.	 Spatial coverage of USGS/BEG lidar data used in compiling the Santa Barbara

	 DEM ..................................................................................................................................16

Figure 15.	 Surface model of unclipped USGS/BEG lidar data at the mouth of the Santa

	 Clara River.........................................................................................................................16

Figure 16.	 Spatial coverage of Ventura County lidar data used in compiling the Santa Barbara

	 DEM ..................................................................................................................................17
Carignan et al., 2009

iv

Figure 17.	 Surface model of unclipped Ventura County lidar data at the mouth of the

	 Santa Clara River...............................................................................................................18

Figure 18.	 CSC IfSAR DEM of West Anacapa Island...............................................................................19

Figure 19.	 Location of the harbor features digitized by NGDC to represent the jetties

	 and breakwaters shown on Google Earth with USACE overlay of features.....................21

Figure 20.	 Location of extracted and digitized land elevations in the Channel Islands region..................22

Figure 21.	 Image of generalized coverage of VDatum transformation tool for the Southern

	 California region................................................................................................................23

Figure 22.	 Histogram of the differences between NOS hydrographic survey H09730 and the

	 1 arc-second pre-surfaced bathymetric grid ......................................................................24

Figure 23.	 Slope map of the Santa Barbara DEM......................................................................................26

Figure 24.	 Perspective view from the southwest of the Santa Barbara DEM............................................27

Figure 25.	 Histogram of the differences between one USGS/BEG lidar survey area and the

	 Santa Barbara DEM...........................................................................................................27

Figure 26.	 Histogram of the differences between NGS geodetic monument elevations and

	 the Santa Barbara DEM ....................................................................................................28

Figure 27.	 Location of NGS geodetic monuments and the NOAA tide stations........................................28

List of Tables

Table 1.	 PMEL specifications for the Santa Barbara DEM ......................................................................2

Table 2.	 Shoreline datasets used in the Santa Barbara DEM....................................................................4

Table 3.	 ENCs available in the Santa Barbara region...............................................................................5

Table 4.	 Bathymetric datasets used in compiling the Santa Barbara DEM..............................................6

Table 5.	 Digital NOS hydrographic surveys available within the Santa Barbara DEM boundary...........8

Table 6.	 CSUMB multibeam sonar surveys used in compiling the Santa Barbara DEM.......................10

Table 7.	 USACE multibeam surveys used in compiling the Santa Barbara DEM.................................12

Table 8.	 NGDC multibeam sonar surveys available in the Santa Barbara DEM region ........................13

Table 9.	 Topographic datasets used in compiling the Santa Barbara DEM............................................15

Table 10.	 Relationship between MHW and other vertical datums used in the Santa Barbara DEM........23

Table 11.	 Data hierarchy used to assign gridding weight in MB-System..................................................25
Digital Elevation Model of Santa Barbara, California:

Procedures, Data Sources and Analysis

1. Introduction

	 In December 2008, the National Geophysical Data Center (NGDC), an office of the National Oceanic and

Atmospheric Administration (NOAA), developed a bathymetric–topographic digital elevation model (DEM) of Santa

Barbara, California (Fig. 1) for the Pacific Marine Environmental Laboratory (PMEL) NOAA Center for Tsunami

Research (http://nctr.pmel.noaa.gov/). The 1/3 arc-secondF

1

F coastal DEM will be used as input for the Method of

Splitting Tsunami (MOST) model developed by PMEL to simulate tsunami generation, propagation and inundation.

The DEM was generated from diverse digital datasets in the region (grid boundary and sources shown in Fig. 3). It will

be used for tsunami forecasting as part of the tsunami forecast system Short-term Inundation Forecasting for Tsunamis

(SIFT) currently being developed by PMEL for the NOAATsunami Warning Centers. This report provides a summary

of the data sources and methodology used in developing the Santa Barbara DEM.

Figure 1. Shaded-relief image of the Santa Barbara DEM. Contour interval is 100 meters.

1. The Santa Barbara DEM is built upon a grid of cells that are square in geographic coordinates (latitude and longitude), however, the cells are not

square when converted to projected coordinate systems, such as UTM zones (in meters). At the latitude of Santa Barbara, California (34° 25′ 33′′ N,

119° 42′ 51′′ W) 1/3 arc-second of latitude is equivalent to 10.271 meters; 1/3 arc-second of longitude equals 8.511 meters.
Carignan et al., 2009

2

2. Study Area

	 The Santa Barbara DEM covers the coastal region surrounding the town of Santa Barbara, California, from

Port Hueneme in the southeast to Point Conception in the northwest, and includes the communities of Port Hueneme,

Oxnard, Ventura, Carpinteria, Santa Barbara, Isla Vista, and Goleta (Fig. 2).

The Channel Islands National Marine Sanctuary is located at the southern boundary of the DEM.

The Channel Islands are home to many species of marine life, providing recreation, educational, and economic benefits

to the surrounding communities as well as research opportunities for the University of California, Santa Barbara. The

coastline varies from sandy beaches to rocky sea cliffs. The Santa Clara River, the largest in Southern California,

empties into the Pacific Ocean south of Oxnard. It flooded in 2005, causing heavy damage and loss of life.

Figure 2. Overview of the Santa Barbara region on NASA World Wind I-cubed image.

3. Methodology

	 The Santa Barbara DEM was constructed to meet PMEL specifications(Table 1), based on input requirements

for the development of reference inundation models (RIMs) and standby inundation models (SIMs) (V. Titov, pers. 

comm.) in support of NOAA’s Tsunami Warning Centers use of SIFT to provide real-time tsunami forecasts in an

operational environment. The best available digital data were obtained by NGDC and shifted to common horizontal

and vertical datums: North America Datum of 1983 (NAD 83) and mean high water (MHW), for modeling of

maximum flooding, respectively.2 Data processing and evaluation, and DEM assembly and assessment are described

in the following subsections.

Table 1: PMEL specifications for the Santa Barbara DEM.

Grid Area Santa Barbara, California

Coverage Area 119.14o to 120.51o W; 33.77o to 34.62o N

Coordinate System Geographic decimal degrees

Horizontal Datum World Geodetic System of 1984 (WGS 84)

Vertical Datum MHW

Vertical Units Meters

Cell Size 1/3 arc-second

Grid Format ESRI Arc ASCII grid

2. The horizontal difference between the North American Datum of 1983 (NAD 83) and World Geodetic System of 1984 (WGS 84) geographic

horizontal datums is approximately one meter across the contiguous U.S., which is significantly less than the cell size of the DEM. Most GIS applications treat the two datums as identical, so do not actually transform data between them, and the error introduced by not converting between

the datums is insignificant for our purposes. NAD 83 is restricted to North America, while WGS 84 is a global datum. As tsunamis may originate

most anywhere around the world, tsunami modelers require a global datum, such as WGS 84 geographic, for their DEMs so that they can model the

wave’s passage across ocean basins. This DEM is identified as having a WGS 84 geographic horizontal datum even though the underlying elevation

data were typically transformed to NAD 83 geographic. At the scale of the DEM, WGS 84 and NAD 83 geographic are identical and may be used

interchangeably.
Digital Elevation Model of Santa Barbara, California

3

3.1 Data Sources and Processing

Shoreline, bathymetric, and topographic digital datasets(Fig. 3) were obtained from several U.S. federal,state

and local agencies and academic institutionsincluding: NOAA’s National Ocean Service (NOS), Office ofCoast Survey

(OCS), Coastal Services Center (CSC); the California State University Seafloor Mapping Laboratory (CSUMB); the

U.S. Geological Survey (USGS); the U.S. Army Corps of Engineers (USACE); the California Department of Fish and

Game (CDFG), and Ventura and Santa Barbara Counties. Safe Software’s FME data translation tool package was used

to shift datasets to NAD 83 horizontal datum and to convert them into ESRI ArcGIS shapefiles3. The shapefiles were

then displayed with ArcGIS to assess data quality and manually edit datasets. Vertical datum transformations to MHW

were accomplished using FME, based upon data from the NOAA Santa Barbara Harbor, Rincon Island, and Bechers

Bay tide stations (http://tidesandcurrents.noaa.gov/) and OCS’s VDatum transformation tool. Applied Imagery’s Quick 

Terrain Modeler software was used to evaluate processing and gridding techniques.

Figure 3. Source and coverage of datasets used in compiling the Santa Barbara DEM.

3. FME uses the North American Datum Conversion Utility (NADCON; http://www.ngs.noaa.gov/TOOLS/Nadcon/Nadcon.html) developed by

NOAA’s National Geodetic Survey (NGS) to convert data from NAD 27 to NAD 83. NADCON is the U.S. Federal Standard for NAD 27 to NAD

83 datum transformations.
Carignan et al., 2009

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3.1.1 Shoreline

Coastline datasets of the Santa Barbara region were obtained from NOAA, CDFG’s Marine Region GIS

Unit, and the San Diego Association of Governments (SANDAG) (Table 2; Fig. 4). Of these four datasets, the OCS’s

Electronic Navigational Charts (ENCs)4 and the CDFG coastline were used to develop a “combined coastline” of the

Santa Barbara region

Table 2: Shoreline datasets used in the Santa Barbara DEM.

Source Year Data Type Spatial 

Resolution

Original Horizontal 

Datum/Coordinate 

System 

Original 

Vertical 

Datum

URL

NOAA

ENCs 2007 Digitalnautical charts

1:40,000 to

1:216,000 WGS 84 geographic MHW http://nauticalcharts.noaa.gov/mcd/enc/

CDFG

Marine

Region

1996

Digitized

1:24,000

USGS quads

1:24,000 NAD 83 geographic Mean

high tide http://www.dfg.ca.gov/marine/

Figure 4. Digital coastline datasets used in developing a combined coastline of the Santa Barbara 

region.

4. The Office of Coast Survey (OCS) produces NOAA Electronic Navigational Charts (NOAA ENC®) to support the marine transportation

infrastructure and coastal management. NOAA ENC®s are in the International Hydrographic Office (IHO) S-57 international exchange format,

comply with the IHO ENC Product Specification and are provided with incremental updates, which supply Notice to Mariners corrections and

other critical changes. NOAA ENC®s are available for free download on the OCS web site. [Extracted from NOAA OCS web site: http://nauticalcharts.noaa.gov/mcd/enc/]
Digital Elevation Model of Santa Barbara, California

5

1) NOAA Electronic Navigational Charts

Four ENCs were available for the Santa Barbara area (Table 3) and downloaded from NOAA’s OCS web

site (http://nauticalcharts.noaa.gov/mcd/enc/). The ENCs are in S-57 format and include coastline data files

referenced to MHW. The coastline from ENC #18727 was adjusted to match high-resolution topographic

data on San Miguel Island and the western half of Santa Rosa Island, and used in the combined coastline for

developing the Santa Barbara DEM.

Table 3: ENCs available in the Santa Barbara region.

Chart # Title Edition Year of Source data Issue Date Scale

18700 Point Conception to Point Sur 6 2003 2008 1:216,116

18720 Point Dume to Purisima Point 8 2000 2008 1:232,188

18725 Port Hueneme to Santa Barbara 15 2003 2008 1:50,000

18727 San Miguel Passage 5 1992 2008 1:40,000

2) California Department of Fish and Game Marine Region GIS Unit coastline

The CDFG coastline was originally developed by the California State Land Commission from digitized

USGS 7.5-minute quadsto define the mean high tide line and wassubsequently rebuilt to reduce tolerances by

the CDFG in 1996. In order to define the current coastline, NGDC analyzed the most recent high-resolution

topographic dataset available and used a derived zero elevation line to manually adjust and clarify location

of the MHW line in the CDFG coastline.

The combined coastline was compared to the most recent high resolution topography datasets and modified

to include coastal features including jetties, rocks, and sand bars. At the mouth of the Santa Clara River, current aerial

photography from the California Coastal Records Project (http://www.californiacoastline.org) was used to determine

the location and shape of the outlet and estuary (Fig. 5). Features such as bridges, piers, and docks were removed using

ArcMap editing tools. The combined coastline was also compared to recent high resolution bathymetric data located in

the harbor at Port Hueneme, Channel Islands, Ventura, and Santa Barbara and edited to ensure inclusion of complete

bathymetric surveys. An xyz file of the combined coastline was generated using GEODAS for use in compiling the

Santa Barbara DEM.

Copyright (C) 2002-2008 Kenneth & Gabrielle Adelman, California Coastal Records Project, http://www.Californiacoastline.org

Figure 5. 2008 aerial photos of the Santa Clara River mouth.
Carignan et al., 2009

6

3.1.2 Bathymetry

Bathymetric datasets available for use in the compilation of the Santa Barbara DEM include 56 NOS

hydrographic surveys; 12 CSUMB near-shore multibeam swath sonar surveys; one USGS multibeam swath

bathymetric sonar survey covering the deeper areas within the Santa Barbara Channel; USACE multibeam data for

the harbors at Santa Barbara, Ventura, Channel Islands Harbor, and Port Hueneme; and 10 multibeam swath sonar

surveys downloaded from the NGDC multibeam bathymetry database (Table 4; Fig. 6).

Table 4: Bathymetric datasets used in compiling the Santa Barbara DEM.

Source Year Data Type Spatial Resolution

Original 

Horizontal Datum/

Coordinate System

Original 

Vertical 

Datum

URL

NGDC 1930 to

2005

NOS

hydrographic

survey

soundings

Ranges from 1

meter to 1 kilometer

(varies with scale of

survey, depth, traffic,

and probability of

obstructions)

NAD 27, NAD

83 geographic or

NAD 83 UTM 11

MLLW http://www.ngdc.noaa.gov/mgg/

bathymetry/hydro.html

CSUMB 2003 to

2008

Multibeam

swath sonar 2 to 3 meters WGS 84 UTMzone 10N and 11N MLLW http://seafloor.csumb.edu/

USGS 2004 Multibeam

swath sonar 15 meters WGS 84geographic MLLW http://geopubs.wr.usgs.gov/open-file/of01-179/

USACE 2007 to

2008

Multibeam

swath sonar 1 to 3 meter grids

NAD 83 California

State Plane zone V

(meters)

MLLW http://www.spl.usace.army.mil/cms/

index.php

NGDC 1989 to

1998

Multibeam

swath sonar 5 meters WGS 84geographic

Assumed

MSL

http://www.ngdc.noaa.gov/mgg/

bathymetry/multibeam.html
Digital Elevation Model of Santa Barbara, California

7

Figure 6. Spatial coverage of the bathymetric datasets used in compiling the Santa Barbara DEM.
Carignan et al., 2009

8

1) National Ocean Service hydrographic survey data

A total of 56 NOS hydrographic surveys conducted between 1930 and 2005 were available for use in

developing the Santa Barbara DEM. The hydrographic survey data were originally vertically referenced to

mean lower low water (MLLW) and horizontally referenced to either NAD 27 or NAD 83 datums. Only 48

of the 56 surveys were used in building the Santa Barbara DEM, as some older surveys have been superseded

(Table 5; Fig. 7).

Data point spacing for the NOS surveys varied by collection date. In general, earlier surveys had greater

point spacing than more recent surveys. Surveys were extracted from NGDC’s NOS Hydrographic Survey

Database (http://www.ngdc.noaa.gov/mgg/bathymetry/hydro.html) referenced to NAD 83. The most recent

survey, H11501, was provided by the NOS Pacific Hydrographic Branch in BAG format and convert to

xyz using CARIS Bathy DataBASE 2.0. The data were then converted to NAD 83 using FME software, an

integrated collection of spatial extract, transform, and load tools for data transformation. The surveys were

subsequently clipped to a polygon 0.05 degrees (~5%) larger than the Santa Barbara DEM area to support

data interpolation along grid edges.

After converting all NOS survey data to MHW using VDatum (see Sec. 3.2.1), the data were displayed

in ESRI ArcMap and reviewed for digitizing errors against scanned original survey smooth sheets and edited

as necessary. The surveys were also compared to the topographic and bathymetric datasets, the combined

coastline, and NOS Raster Navigational Charts (RNCs). The surveys were clipped to remove soundings that

overlap the more recent multibeam swath sonar surveys and where soundings from older surveys have been

superseded by more recent NOS surveys.

Table 5: Digital NOS hydrographic surveys available within the Santa Barbara DEM boundary.

NOS Survey ID Year of Survey Survey Scale Original Vertical Datum Original Horizontal Datum of 

Digital Records

H05030* 1930 80,000/20,000 MLLW NAD 27

H05419* 1933 5,000 MLLW NAD 27

H05420 1933 10,000 MLLW NAD 27

H05426 1933 10,000 MLLW NAD 27

H05463* 1933 10,000 MLLW NAD 27

H05498* 1933 10,000 MLLW NAD 27

H05499* 1933 10,000 MLLW NAD 27

H05502 1933 10,000 MLLW NAD 27

H05503 1933 10,000 MLLW NAD 27

H05624 1933 10,000 MLLW NAD 27

H05625 1933 10,000 MLLW NAD 27

H05626* 1933 10,000 MLLW NAD 27

H05627 1933 10,000 MLLW NAD 27

H05445 1933 20,000 MLLW NAD 27

H05464* 1933 5,000 MLLW NAD 27

H05508 1933 10,000 MLLW NAD 27

H05775 1933 120,000 MLLW NAD 27

H05425* 1933 10,000 MLLW NAD 27

H05446 1933/34 40,000 MLLW NAD 27

H05660 1934 20,000 MLLW NAD 27

H05661 1934 5,000 MLLW NAD 27

H05509 1934 10,000 MLLW NAD 27

H05746 1934 40,000 MLLW NAD 27

H05776 1934 120,000 MLLW NAD 27

H05830 1934 40,000 MLLW NAD 27

H05849 1934 40,000 MLLW NAD 27

H05662 1935 10,000 MLLW NAD 27

H05683 1935 20,000 MLLW NAD 27

H05695 1935 20,000 MLLW NAD 27
Digital Elevation Model of Santa Barbara, California

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NOS Survey ID Year of Survey Survey Scale Original Vertical Datum Original Horizontal Datum of 

Digital Records

H05696 1935 10,000 MLLW NAD 27

H05699 1935 20,000 MLLW NAD 27

H05700 1935 20,000 MLLW NAD 27

H05701 1935 20,000 MLLW NAD 27

H05773 1935 40,000 MLLW NAD 27

H05850 1935 40,000 MLLW NAD 27

H05851 1935 80,000 MLLW NAD 27

H05860 1935 40,000 MLLW NAD 27

H05861 1935 80,000 MLLW NAD 27

H06258 1937 80,000 MLLW NAD 27

H06259 1937 80,000 MLLW NAD 27

H09666 1976 5,000 MLLW NAD 27

H09667 1976 10,000 MLLW NAD 27

H09725 1977 20,000 MLLW NAD 27

H09728 1977 20,000 MLLW NAD 27

H09730 1977 20,000 MLLW NAD 27

H09732 1977 20,000 MLLW NAD 27

H09741 1978 10,000 MLLW NAD 27

H09751 1978 5,000 MLLW NAD 27

H09752 1978 20,000 MLLW NAD 27

H09740 1978 5,000 MLLW NAD 27

H10161 1984 20,000 MLLW NAD 27

H10164 1984 20,000 MLLW NAD 27

H10165 1984/85 10,000 MLLW NAD 27

H10171 1985 20,000 MLLW NAD 27

H11024 2001 10,000 MLLW NAD 83

H11501 2005 5,000 MLLW NAD 83 UTM 11 N meters

* survey not used in building the Santa Barbara DEM

Figure 7. Digital NOS hydrographic survey coverage in the Santa Barbara region. DEM boundary in red.
Carignan et al., 2009

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2) California State University Seafloor Mapping Laboratory multibeam sonar surveys

Twelve near shore multibeam swath sonar surveys were downloaded from the CSUMB web site (http://

seafloor.csumb.edu/) as gridded data or xyz files (Table 6, Fig. 8). The surveys were collected from 2003 to

2008, and referenced to WGS 84, UTM zone 10N, or zone 11N and MLLW vertical datum. The files were

converted to NAD 83 and to MHW using the VDatum transformation tool. The surveys were reviewed and

edited as necessary to remove anomalous data points using QT Modeler and ArcMap.

Table 6: CSUMB multibeam sonar surveys used in compiling the Santa Barbara DEM.

Survey ID Year Original Vertical 

Datum Original Horizontal Datum Type

Channel Islands Santa Rosa Island –

Carrington Point 2003 MLLW WGS1984 UTM zone 10N 3 meter grid

Channel Islands Santa Rosa Island –

South Point 2003 MLLW WGS1984 UTM zone 10N 3 meter grid

Channel Islands Santa Cruz Island –

Gull Island 2003 MLLW WGS1984 UTM zone 11N 3 meter grid

Channel Islands Santa Cruz Island –

Scorpion Point 2006 MLLW WGS1984 UTM zone 11N* 2 meter xyz

Santa Barbara Channel A 2008 MLLW WGS1984 UTM zone 10N* 2 meter xyz

Santa Barbara Channel B 2008 MLLW WGS1984 UTM zone 10N* 2 meter xyz

Santa Barbara Channel C 2008 MLLW WGS1984 UTM zone 10N* 2 meter xyz

Santa Barbara Channel D 2008 MLLW WGS1984 UTM zone 10N* 2 meter xyz

Santa Barbara Channel E 2007 MLLW WGS1984 UTM zone 10N* 2 meter xyz

Santa Barbara Channel F 2007 MLLW WGS1984 UTM zone 10N* 2 meter xyz

Santa Barbara Channel G 2007 MLLW WGS1984 UTM zone 10N* 2 meter xyz

Santa Barbara Channel H 2007 MLLW WGS1984 UTM zone 10N* 2 meter xyz

* xyz files are assumed to be in the same horizontal datum as the grids.

Figure 8. Spatial coverage of CSUMB multibeam swath sonar surveys used in compiling the Santa Barbara DEM.
Digital Elevation Model of Santa Barbara, California

11

3) U.S. Geological Survey multibeam swath sonar survey

The USGS conducted a multibeam swath sonar survey along the California coast within the DEM

boundary (Fig. 9). The 15-meter gridded survey data were downloaded in ASCII xyz format from the USGS

Data Catalog web site (http://pubs.usgs.gov/of/2005/1153/) in WGS 84 geographic horizontal datum and

MLLW vertical datum. The data were converted from MLLW to MHW using the VDatum transformation

tool.

Figure 9. Shaded-relief image showing spatial coverage of the 2004 USGS multibeam swath sonar survey. 

Image taken from USGS Open File Report 2005-1153.
Carignan et al., 2009

12

4) U.S. Army Corps of Engineers multibeam bathymetric surveys

USACE dredges and maintains the harbors at Santa Barbara, Ventura, and Port Hueneme (Fig.10).

Four multibeam bathymetric surveys were provided to NGDC in gridded form for use in building the Santa

Barbara DEM. The 1 to 3 meter resolution grids provide dense coverage at the entrance and within the

harbors. The surveys were converted to point shapefiles and transformed to NAD 83 using FME and MHW

using the VDatum tool.

Table 7: USACE multibeam bathymetric surveys used in compiling the Santa Barbara DEM.

Survey Date Type Resolution Horizontal Datum Vertical Datum

Channel Islands

Harbor 2008 Multibeam swathsonar 1 meter grid NAD 83 California StatePlane zone V MLLW

Port Hueneme 2007 Multibeam swath

sonar 3 meter grid NAD 83 California StatePlane zone V MLLW

Santa Barbara

Harbor 2008 Multibeam swathsonar 1 meter grid NAD 83 California StatePlane zone V MLLW

Ventura Harbor 2008 Multibeam swath

sonar 1 meter grid NAD 83 California StatePlane zone V MLLW

Figure 10. Spatial coverage of USACE multibeam bathymetric surveys used in compiling the Santa Barbara DEM.
Digital Elevation Model of Santa Barbara, California

13

5) NGDC multibeam swath sonar surveys

Ten multibeam swath sonar surveys from University of California/Scripps Institute of Oceanography

(SIO), Monterey Bay Aquarium Research Institute (MBARI) and Columbia University/Lamont-Doherty

Earth Observatory (CU/LDEO) were downloaded from the NGDC Multibeam Bathymetry Database (http://

www.ngdc.noaa.gov/mgg/bathymetry/multibeam.html; Table 8). The most recent survey, Channel, covers a

large portion of the Santa Barbara Channel and supersedes the earlier nine surveys available (Fig. 11). This

was the only survey used in compiling the Santa Barbara DEM. The survey was gridded using MB-System

into smaller sections and converted to xyz format, then transformed from MSL to MHW using the VDatum

tool. The eastern section of the survey approaches and enters the Port Hueneme Harbor. Elevations in this

area were not consistent with the USACE survey or NOS survey H11024 and were removed using FME (Fig.

12).

Table 8: NGDC multibeam sonar surveys available in the Santa Barbara DEM region.

Survey ID Year Original Vertical Datum Institute Ship

CALF01RR 1996 Assumed MSL SIO Roger Revelle

CALF03RR 1996 Assumed MSL SIO Roger Revelle

Channel 1998 Assumed MSL MBARI Ocean Alert

EW9414 1994 Assumed MSL CU/LDEO Ewing

NPAL98MV 1998 Assumed MSL SIO Melville

REM01MV 1993 Assumed MSL SIO Melville

REM02MV 1993 Assumed MSL SIO Melville

RNDB18WT 1989 Assumed MSL SIO Thomas Washington

TUNE01WT 1991 Assumed MSL SIO Thomas Washington

WEST15MV 1995 Assumed MSL SIO Melville

Figure 11. Spatial coverage of NGDC multibeam bathymetric data used in compiling the Santa Barbara DEM.
Carignan et al., 2009

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Figure 12. Detail of section of Channel multibeam bathymetric survey removed from the dataset. 

Purple denotes survey coverage, cross hatched region was deleted.
Digital Elevation Model of Santa Barbara, California

15

3.1.3 Topography

	 Five topographic datasets in the Santa Barbara region were obtained from Ventura County, USGS, CSC, and

OCS, and used to build the Santa Barbara DEM (Table 9; Fig. 13). NGDC evaluated, but did not use, the Shuttle Radar

Topography Mission (SRTM) Elevation 1 arc-second DEM available from USGS or CSC lidar data from 1998. NGDC

digitized some elevation points to supplement the available datasets at Santa Barbara, Ventura, Channel Islands, and

Port Hueneme Harbors. The lidar data and topographic DEMs were referenced to North American Vertical Datum of

1988 (NAVD88).

Table 9: Topographic datasets used in compiling the Santa Barbara DEM.

Source Year Data Type Spatial

Resolution

Original Horizontal 

Datum/Coordinate 

System

Original 

Vertical 

Datum

URL

USGS/BEG 2005 Lidar 1 meter NAD 83 UTM zone

11N (meters) NAVD88

Ventura

County 2005 Bare-earth lidar 1 meter NAD 83 CaliforniaState Plane V (feet) NAVD88

CSC 2002/2003 IfSAR DEMs 3 meters WGS 84 (geographic) NAVD88 http://csc.noaa.gov/digitalcoast/

USGS 1999-2005 NED DEM 1/3 arcsecond NAD 83 (geographic) NAVD88 http://ned.usgs.gov/

NGDC Digitized

elevation points

~2.5

meters WGS 84 (geographic) MHW

NOAA ENC Digital nautical

charts WGS 84 (geographic) MHW

Figure 13. Spatial coverage of the topographic datasets used in compiling the Santa Barbara DEM.
Carignan et al., 2009

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1) U.S. Geological Survey/Bureau of Economic Geology bare-earth lidar

USGS provided NGDC with bare-earth coastal lidar data (Fig. 14) surveryed in October 2005 by the

Bureau of Economic Geology (BEG), University of Texas at Austin. The data cover the California coastline

from Point Mugu to Point Conception and was collected to monitor coastal change. The ASCII data files were

converted to point shapefiles and used to adjust the combined coastline. Anomalous elevation values over

water were clipped to the combined coastline with the exception of those in the Santa Clara River outlet (Fig.

15). Elevation values in the river channel were more effective at creating a shallow depth for the channel in

the final DEM than removing the values in the channel.

Figure 14. Spatial coverage of USGS/BEG lidar data used in compiling the Santa Barbara DEM.

Figure 15. Surface model of unclipped USGS/BEG lidar data at the mouth of the Santa Clara River. Note returns from waves nearing beach.
Digital Elevation Model of Santa Barbara, California

17

2) Ventura County lidar

Ventura County provided NGDC with bare-earth lidar point data flown in February of 2005 (Fig. 16). The

point data were transformed to NAD 83 and MHW with FME and clipped to the combined coastline except

within the Santa Clara River channel. Data were not clipped in the channel because there were no bathymetric

surveys available. The returns reflected a more accurate surface than if clipping it to the coastline (Fig. 17).

Figure 16. Spatial coverage of Ventura County lidar data used in compiling the Santa Barbara DEM.
Carignan et al., 2009

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Figure 17. Surface model of unclipped Ventura County lidar data at the mouth of the Santa Clara River. 

Note returns from waves nearing beach.
Digital Elevation Model of Santa Barbara, California

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3) Coastal Services Center IfSAR DEMs

Interferometric Synthetic Aperture Radar (IfSAR) DEMs were downloaded from the CSC web site

covering Santa Barbara County and the Channel Islands. The dataset was developed to support watershed

analysis in the Southern California coastal environment. The DEMs were clipped to the coastline and

transformed to MHW using ArcCatalog tools, and converted to xyz format with FME. The dataset is not

processed to bare earth and was not edited prior to building the Santa Barbara DEM. The IfSAR data were

used primarily for inland areas of Santa Barbara County and the Channel Islands, excluding Anacapa Island.

DEM data encompassing Anacapa Island contained topographic values inconsistent with the rest of the

dataset (Fig. 18).

Figure 18. CSC IfSAR DEM of West Anacapa Island. Blue shades over ocean have elevation at MHW of .38 to 1 meter.
Carignan et al., 2009

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4) U.S. Geological Survey NED topographic DEM

USGS’s National Elevation Dataset (NED) provides complete 1/3 arc-second coverage of the Santa

Barbara regionF

5

F. Data are in NAD 83 geographic coordinates and NAVD88 vertical datum (meters), and

are available for download as raster DEMs. The bare-earth elevations have a vertical accuracy of +/- 7 to 15

meters depending on source data resolution (see the USGS Seamless web site for specific source information:

http://seamless.usgs.gov). The dataset was derived from USGS quadrangle maps and aerial photographs

based on topographic surveys; it has been revised using data collected in 1999 and 2005. The NED data were

used on Anacapa Island as a substitution for the higher resolution IfSAR data available throughout the DEM

region. The NED DEM included “zero” elevation values over the open ocean, which were removed from

the dataset by clipping to the combined coastline. The data were then converted to xyz points and filtered to

remove “zero” elevations within the combined coastline.

5) NGDC digitized elevation points

To represent the jetties at Santa Barbara, Ventura, Channel Islands, and Port Hueneme Harbors (Fig. 19),

NGDC created digital representations of the features using ArcMap and assigned elevations. The elevation

for the Santa Barbara breakwater was set at 2.5 meters. The elevations for the features at Port Hueneme

and Channel Islands harbors were set at 2.5 meters and features at Ventura Harbor were set at 4.5 and 5.5

meters, referencing the USACE’s Enterprise Coastal Inventory Database (http://chl.erdc.usace.army.mil/chl.

aspx?p=s&a=Projects;246). The point spacing for all digitized features is ~2.5 meters to ensure an even

surface on the tops of the features.

5. The USGS National Elevation Dataset (NED; http://ned.usgs.gov/) has been developed by merging the highest-resolution, best quality elevation data available across the United States into a seamless raster format. NED is the result of the maturation of the USGS effort to provide

1:24,000-scale Digital Elevation Model (DEM) data for the conterminous U.S. and 1:63,360-scale DEM data for Georgia. The dataset provides

seamless coverage of the United States, HI, AK, and the island territories. NED has a consistent projection (Geographic), resolution (1 arc-second),

and elevation units (meters). The horizontal datum is NAD 83, except for AK, which is NAD 27. The vertical datum is NAVD88, except for AK,

which is NGVD29. NED is a living dataset that is updated bimonthly to incorporate the “best available” DEM data. As more 1/3 arc-second (10 m)

data covers the U.S., then this will also be a seamless dataset. [Extracted from USGS NED web site]
Digital Elevation Model of Santa Barbara, California

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Figure 19. Location of the harbor features digitized by NGDC to represent the jetties and breakwaters shown on Google Earth with USACE 

overlay of features. A) Santa Barbara breakwater. B) Ventura Harbor jetties and breakwater. C) Port Hueneme and Channel Islands Harbor 

jetties and breakwaters.
Carignan et al., 2009

22

6) NOAA Electronic Navigational Chart extracted land elevation points

Many of the offshore rocks and islets in the Channel Islands were not fully resolved in the digital

topographic elevation datasets. To include these features, land elevation points were extracted from

ENC #18727 and digitized referencing RNCs #18728 and #18729 (Fig. 20). ENC land elevation data are

referenced to MHW and WGS 84. RNC elevation data are in units of feet and were converted to meters

before incorporating into the final gridding process.

Figure 20. Location of extracted and digitized land elevations shown as red triangles in the Channel Islands region.
Digital Elevation Model of Santa Barbara, California

23

3.2 Establishing Common Datums

3.2.1 Vertical datum transformations

Datasets used in the compilation and evaluation of the Santa Barbara DEM were originally referenced to a

number of vertical datums including MLLW, mean sea level (MSL), and NAVD88. All datasets were transformed to

MHW to provide maximum flooding for inundation modeling.

1) Bathymetric data

The NOS hydrographic surveys, and multibeam swath sonar surveys were transformed from MLLW and

MSL to MHW, using the VDatum transformation tool (Fig. 21).

Figure 21. Image of generalized coverage of VDatum transformation tool for the Southern California region. 

Santa Barbara DEM boundary in yellow.

2) Topographic data

The USGS NED 1/3 arc-second DEM, lidar data, and the CSC IfSAR DEMs were originally referenced

to NAVD88. As the VDatum transformation tool is not available further inland, conversion to MHW using

FME software and ArcCatalog, was accomplished by adding a constant offset of -1.394 meters (Table 10),

the average difference from NAVD88 to MHW at the Santa Barbara Harbor, Rincon Island, and Bechers Bay

tide stations (#9411340, #9411270, and #9410962; Fig.27).

Table 10. Relationship between MHW and other vertical datums used in the Santa Barbara DEM.

Santa Barbara Harbor Rincon Island Bechers Bay Average

MSL to MHW -0.563 -0.573 -0.532 -0.556

NAVD88 to MHW -1.384 -1.404 -1.394

MLLW to MHW -1.413 -1.434 -1.346 -1.398

3.2.2 Horizontal datum transformations

Datasets used in compiling the Santa Barbara DEM were originally referenced to WGS 84 geographic, WGS

84 UTM zone 10 and zone 11N, NAD 83 California State Plane V (feet or meters), NAD 83 UTM zone 1N, NAD

83 geographic, or NAD 27 geographic horizontal datums. The relationships and transformational equations between

these horizontal datums are well established. All data were converted to a horizontal datum of NAD 83 geographic

using FME software or ArcGIS tools.
Carignan et al., 2009

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3.3 Digital Elevation Model Development

3.3.1 Verifying consistency between datasets

After horizontal and vertical transformations were applied, the resulting ESRI shapefiles were checked in

ArcMap for consistency between datasets. Problems and errors were identified and resolved before proceeding with

subsequent gridding steps. The evaluated and edited ESRI shapefiles were then converted to xyz files in preparation

for gridding. Problems included:

•	 Suspect topographic elevations located close to shore.

•	 Data values over the ocean and rivers in the topographic datasets. The datasets required automated clipping

to the combined coastline.

•	 Topographic IfSAR dataset not processed to bare earth.

•	 Digital, measured bathymetric values from NOS surveys date back over 70 years. More recent data, such

as the multibeam surveys differ from older NOS data by as much as 100 meters vertically. The older NOS

survey data were excised where more recent bathymetric data exists.

3.3.2 Smoothing of bathymetric data

The older NOS hydrographic surveys are generally sparse at the resolution of 1/3 arc-second DEM in both

deep water and in some areas close to shore. In order to reduce the effect of artifactsin the form of lines of “pimples” in

the DEM due to this low resolution dataset and to provide effective interpolation into the coastal zone, a 1 arc-secondspacing “pre-surface” bathymetric grid was generated using GMT, an NSF-funded shareware software application

designed to manipulate data for mapping purposes.

	 The NOS hydrographic point data, in xyz format, were clipped to remove overlap with the USGS, USACE,

CSUMB, and NGDC multibeam data and then combined with points extracted from the combined coastline to provide

a buffer along the entire coastline. The coastline elevation value was set at -1.0 m to ensure a bathymetric surface

below zero in areas where bathymetric data are sparse or nonexistent.

	 The point data were median-averaged using the GMT tool “blockmedian” to create a 1 arc-second grid 0.05

degrees (~5%) larger than the Santa Barbara DEM gridding region. The GMT tool “surface” was then used to apply

a tight spline tension to interpolate elevations for cells without data values. The GMT grid created by “surface” was

converted into an ESRI Arc ASCII grid file, and clipped to the combined coastline (to eliminate data interpolation into

land areas). The resulting surface was compared with original soundings to ensure grid accuracy (e.g., Fig. 22) and

exported as an xyz file for use in the final gridding process (see Table 11).

	 Some inconsistencies were identified while merging the bathymetric datasets due to the range in ages and

resolutions of the NOS hydrographic surveys. Coastal erosion and development, and changes in the harbor structure

and design have modified the coastline. In areas where more recent data were available, the older surveys were either

edited or removed.

Figure 22. Histogram of the differences between NOS hydrographic survey H09730 and the 1 arc-second pre-surfaced 

bathymetric grid.
Digital Elevation Model of Santa Barbara, California

25

3.3.3 Gridding the data with MB-System

MB-System was used to create the 1/3 arc-second Santa Barbara DEM. MB-System is an NSF-funded

shareware software application specifically designed to manipulate submarine multibeam sonar data, though it can

utilize a wide variety of data types, including generic xyz data. The MB-System tool “mbgrid” was used to apply a tight

spline tension to the xyz data, and interpolate values for cells without data. The data hierarchy used in the “mbgrid”

gridding algorithm, as relative gridding weights, is listed in Table 11. Greatest weight was given to the USACE

multibeam data, the land elevation data, and harbor features. Least weight was given to the pre-surfaced 1 arc-second

bathymetric grid. Gridding was performed in quadrants with the resulting Arc ASCII grids seamlessly merged in

ArcCatalog to create the final 1/3 arc-second Santa Barbara DEM.

Table 11. Data hierarchy used to assign gridding weight in MB-System.

Dataset Relative Gridding Weight

USGS/BEG coastal lidar 1000

CSC topographic IfSAR DEMs 100

USGS NED topographic DEM 100

Ventura County topographic lidar 100

ENC land elevations and NGDC digitized topographic harbor features 10,000

Combined coastline 1

USGS multibeam survey 100

CSUMB multibeam surveys 1000

NOS hydrographic surveys 10

USACE multibeam surveys 10,000

NGDC multibeam survey 100

Pre-surfaced bathymetric grid 1

3.4 Quality Assessment of the DEM

3.4.1. Horizontal accuracy

The horizontal accuracy of topographic and bathymetric features in the Santa Barbara DEM is dependent

upon DEM cell size and the datasets used to determine corresponding DEM cell values. Topographic features have

an estimated accuracy of 10 meters: USGS/BEG lidar, Ventura County lidar, and CSC topographic IfSAR data have

accuracy better than 2 meters; NED topography is accurate to within about 10 meters. Bathymetric features are

resolved only to within a few tens of meters in deep-water areas. Shallow, near-coastal regions, rivers, and harbor

surveys have an accuracy approaching that of subaerial topographic features. Positional accuracy is limited by the

sparseness of deep-water soundings, potentially large positional uncertainty of pre-satellite navigated (e.g., GPS) NOS

hydrographic surveys, and by the morphologic change that occurs in this dynamic coastal region.

3.4.2 Vertical accuracy

Vertical accuracy of elevation values for the Santa Barbara DEM is also highly dependent upon the source

datasets contributing to DEM cell values. Topographic areas have an estimated vertical accuracy better than 1 meter

for USGS/BEG lidar, Ventura County lidar, and CSC topographic IfSAR data, and up to 7 meters for NED topography.

Bathymetric areas have an estimated accuracy of between 0.1 meters and 5% of water depth. Those values were

derived from the wide range of input data sounding measurements from the early 20th century to recent, GPS-navigated

sonar surveys. Gridding interpolation to determine values between sparse, poorly-located NOS soundings degrades

the vertical accuracy of elevations in deep water.
Carignan et al., 2009

26

3.4.3 Slope maps and 3-D perspectives

ESRI ArcCatalog was used to generate a slope grid from the Santa Barbara DEM to allow for visual inspection

and identification of artificial slopes along boundaries between datasets (e.g., Fig. 23). The DEM was transformed

to UTM zone 11 coordinates (horizontal units in meters) in ArcCatalog for derivation of the slope grid; equivalent

horizontal and vertical units are required for effective slope analysis. Three-dimensional viewing of the DEM was

accomplished using QT Modeler. Figure 24 shows a perspective rendering generated using ArcMap. Analysis of

preliminary grids revealed suspect data points, which were corrected before recompiling the DEM. Figure 1 shows a

color image of the 1/3 arc-second Santa Barbara DEM in its final version.

Figure 23. Slope map of the Santa Barbara DEM. Flat-lying slopes are white; dark shading denotes 

steep slopes; combined coastline in red.
Digital Elevation Model of Santa Barbara, California

27

Figure 24. Perspective view from the southwest of the Santa Barbara DEM. Vertical 

exaggeration-times 2.

3.4.4 Comparison with source data files

To ensure grid accuracy, the Santa Barbara DEM was compared to select source data files. Files were chosen

on the basis of their contribution to the grid-cell values in their coverage areas (i.e., had the greatest weight and did

not significantly overlap other data files with comparable weight). A histogram of the differences between a USGS/

BEG topographic lidar survey area and the Santa Barbara DEM is shown in Figure 25. Differences cluster around zero,

elevation points with large difference values generally occurring in steep terrain.

Figure 25. Histogram of the differences between one USGS/BEG lidar survey area and the Santa Barbara DEM.
Carignan et al., 2009

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3.4.5 Comparison with National Geodetic Survey geodetic monuments

The elevations of 1175 geodetic monuments were extracted from the NOAA NGS web site (http://www.ngs.

noaa.gov/) in shapefile format (see Fig. 27 for monument locations). Shapefile attributes give monument positions

in NAD 83 (typically sub-mm accuracy) and elevations in NAVD88 (in meters). Elevations were shifted to MHW

vertical datum (see Table 10) for comparison with the Santa Barbara DEM (Fig. 26). Differences between the Santa

Barbara DEM and the NGS geodetic monument elevations range from -442 to 508 meters, the majority of which are

within U+U 2 meters. Negative values indicate that the DEM monument elevation is less than the monument elevation.

Only 110 monuments out of 1175 total showed significant deviations from the DEM. These discrepancies are generally

caused by the rough local terrain, where significant changes in relief occur on the scale of less then 10 meters. Larger

discrepancies occurred where monument elevations are incorrect in the NGS database.

Figure 26. Histogram of the differences between NGS geodetic monument elevations and the Santa Barbara DEM.

Figure 27. Location of NGS geodetic monuments, shown as green triangles, and the NOAA tide stations, 

shown as black circles. 
Digital Elevation Model of Santa Barbara, California

29

4. Summary and Conclusions

	 A bathymetric–topographic DEM of the Santa Barbara, California region, with cell size of 1/3 arc-second,

was developed for the PMEL NOAA Center for Tsunami Research. The best available digital data from U.S. federal,

state and local agencies and academic institutions were obtained by NGDC, shifted to common horizontal and vertical

datums, and evaluated and edited before DEM generation. The data were quality checked, processed and gridded

using ArcGIS, FME, CARIS, GMT, MB-System and Quick Terrain Modeler software.

Recommendations to improve the Santa Barbara DEM, based on NGDC’s research and analysis, are listed below:

•	 Conduct hydrographic surveys for near-shore areas, especially in harbors.

•	 Conduct bathymetric–topographic lidar surveys of entire region.

•	 Conduct deep-water multibeam surveys for region south of Channel Islands.

•	 Process IfSAR DEMs to bare earth.

5. Acknowledgments

	 The creation of the Santa Barbara DEM was funded by NOAA PMEL. The authors thank Nazila Meratia and

Vasily Titov (PMEL), Patrick Barnard (USGS, Santa Cruz), Peter Darnell (USGS, Menlo Park), Roger Adams (City

of Ventura), Karen Mendoza (Ventura County, Watershed Protection District), Zacharias Hunt (County Geographic

Information Officer, Santa Barbara County), Alan Nichols and Brooks Hubbard (USACE Los Angeles District

Office), and Susan Jordan (California Coastal Protection Network). Multibeam data used in this study were acquired,

processed, archived, and distributed by the Seafloor Mapping Laboratory of California State University, Santa Barbara

Bay.

6. References

Nautical Chart #18700 (ENC), 6th Edition, 2008. Point Conception to Point Sur. Scale 1: 216,116. U.S. Department

of Commerce, NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18720 (ENC), 8th Edition, 2008. Point Dume to Purisima Point. Scale 1:232,188. U.S. Department of

Commerce, NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18725 (ENC), 15th Edition, 2008. Port Hueneme to Santa Barbara. Scale 1:50,000. U.S. Department

of Commerce, NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18727 (ENC), 5th Edition, 2008. San Miguel Passage. Scale 1:40,000. U.S. Department of Commerce,

NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18721 (RNC), 11th Edition, 2008. Santa Cruz Island to Purisima Point. Scale 1:100,000. U.S.

Department of Commerce, NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18724 (RNC), 1st Edition, 2008. Port Hueneme. Scale 1:20,000. U.S. Department of Commerce,

NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18728 (RNC), 9th Edition, 2008. Santa Cruz Channel. Scale 1:40,000. U.S. Department of Commerce,

NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18729 (RNC), 13th Edition, 2008. Anacapa Passage. Scale 1:40,000. U.S. Department of Commerce,

NOAA, National Ocean Service, Coast Survey.
Carignan et al., 2009

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7. Data Processing Software

ArcGIS v. 9.2 – developed and licensed by ESRI, Redlands, California, http://www.esri.com/

CARIS Bathy DataBASE 2.0, bathymetric data processing software developed and licensed by CARIS, Fredericton,

NB, Canada, http://www.caris.com/

FME 2008 GB – Feature Manipulation Engine, developed and licensed by Safe Software, Vancouver, BC, Canada,

http://www.safe.com/

GEODAS v. 5 – Geophysical Data System, freeware developed and maintained by Dan Metzger, NOAA National

Geophysical Data Center, http://www.ngdc.noaa.gov/mgg/geodas/

GMT v. 4.1.4 – Generic Mapping Tools, freeware developed and maintained by Paul Wessel and Walter Smith, funded

by the National Science Foundation, http://gmt.soest.hawaii.edu/

MB-System v. 5.1.0 – shareware developed and maintained by David W. Caress and Dale N. Chayes, funded by the

National Science Foundation, http://www.ldeo.columbia.edu/res/pi/MB-System/

Quick Terrain Modeler v. 6.0.1 – lidar processing software developed by John Hopkins University’s Applied Physics

Laboratory and maintained and licensed by Applied Imagery, http://www.appliedimagery.com/