noaa / NATIONAL OCEANIC AND

ATMOSPHERIC ADMINISTRATION

National Environmental Satellite,

Data, and Information Service

NOAA Technical Memorandum NESDIS NGDC-61

DIGITAL ELEVATION MODEL OF HANALEI, HAWAII :

PROCEDURES, DATA SOURCES AND ANALYSIS 

K.S. Carignan

L.A. Taylor

B.W. Eakins

D.Z. Friday

P.R. Grothe

E. Lim

M.R. Love

National Geophysical Data Center

Marine Geology and Geophysics Division

Boulder, Colorado

August 2012

UNITED STATES

DEPARTMENT OF COMMERCE

Rebecca Blank

Acting 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-61

DIGITAL ELEVATION MODEL OF HANALEI, HAWAII:

PROCEDURES, DATA SOURCES AND ANALYSIS 

Kelly S. Carignan1 

Lisa A. Taylor2

Barry W. Eakins1

Dorothy Z. Friday1 

Pamela R. Grothe1 

Elliot Lim1 

Matthew R. Love1

1Cooperative 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

August 2012
Carignan et al., 2012

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/coastal/

Also available from the National Technical Information Service (NTIS)

(http://www.ntis.gov)

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Digital Elevation Model of Hanalei, Hawaii

Contents

1..Introduction 1

2..Study Area 2

3..Methodology 3

3.1 Data Sources and Processing 4

3.1.1 Coastline 5

3.1.2 Bathymetry 7

3.1.3 Topography 12

3.2 Establishing Common Datums 14

3.2.1 Vertical datum transformations 14

3.2.2 Horizontal datum transformations 14

3.3 Digital Elevation Model Development 15

3.3.1 Verifying consistency between datasets 15

3.3.2 Smoothing of bathymetric data 15

3.3.3 Building the 1/3 arc-second MHW DEM 17

3.4 Quality Assessment of the DEM 17

3.4.1 Horizontal accuracy 17

3.4.2 Vertical accuracy 17

3.4.3 Slope map, 3-D perspective and data contribution plot 18

3.4.4 MHW DEM comparison with source data files 20

3.4.5 Comparison with National Geodetic Survey geodetic monuments 22

4..Summary and Conclusions 23

5..Acknowledgments 23

6..References 24

7..Data Processing Software 24

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Carignan et al., 2012

List of Tables

Table 1. PMEL specifications for the 1/3 arc-second Hanalei, Hawaii DEM. 3

Table 2. Shoreline dataset used in building the Hanalei, Hawaii DEM. 5

Table 3. Bathymetric datasets used in compiling the Hanalei, Hawaii DEM. 7

Table 4. JALBTCX / SHOALS hydrographic surveys used in compiling the Hanalei, Hawaii DEM. 8

Table 5. Multibeam swath sonar surveys used in compiling the Hanalei, Hawaii DEM. 9

Table 6. Nautical charts available in the Hanalei, Hawaii region. 11

Table 7. Topographic datasets used in compiling the Hanalei, Hawaii DEM. 12

Table 8. Relationships between MHW and other vertical datums in meters within the Hanalei, Hawaii

DEM region. 14

Table 9. Data hierarchy used to assign gridding weight in MB-System 17

List of Figures

Figure 1. Shaded relief image of the Hanalei, Hawaii DEM. Contour intervals for bathymetry are 100

meters and 200 meters for topography. 1

Figure 2. Map of the Hawaiian Island Chain and the location of the Hanalei, Hawaii DEM boundary,

shown as red box. 2

Figure 3. Source and coverage of datasets used in building the Hanalei, Hawaii DEM. 4

Figure 4. Comparison of ENC MHW shoreline and CCMA coastline 5

Figure 5. Spatial coverage of the JALBTCX / SHOALS hydrographic lidar surveys used in developing

the Hanalei DEM. Red solid line denotes the DEM boundary and the green dashed line

denotes extent of data (See Sec. 3.0). 8

Figure 6. Spatial coverage of the NGDC multibeam survey data available in the Hanalei, Hawaii region.

10

Figure 7. An example of swath edits made in multibeam survey KRUS05RR. Red arrows point to areas

where returns were suspect and removed before re-gridding. 10

Figure 8. Spatial data coverage of digitized RNC soundings. 11

Figure 9. A comparison of FEMA and JALBTCX lidar at Anahola Bay. Cross section shows majority of

elevation values match. 13

Figure 10. Histgram of differences between the 1 arc-second bathymetric surface and multibeam survey

AVON07MV. 16

Figure 11. Slope map of the Hanalei DEM. 18

Figure 12. A perspective image of the Hanalei DEM. View is from the northeast and vertical

exaggeration is 2x. 19

Figure 13. Histogram of the differences between the multibeam survey NBP0304B and the Hanalei

DEM. 20

Figure 14. Histogram of differences between a sample set of JALBTCX / PSC lidar data and the Hanalei

DEM. 21

Figure 15. Histogram of differences between a sample set of FEMA lidar data and the Hanalei DEM. 21

Figure 16. Location of NGS monuments within the Hanalei DEM boundary, in red. Tide stations are

labeled. 22

Figure 17. Histogram of the differences between the NGS monument elevations and the Hanalei DEM.

23

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Digital Elevation Model of Hanalei, Hawaii

Digital Elevation Model of Hanalei, Hawaii:

Procedures, Data Sources and Analysis

1. Introduction

In March 2011 The National Geophysical Data Center (NGDC), an office of the National Oceanic and Atmospheric Administration (NOAA), developed an integrated bathymetric–topographic digital elevation model (DEM) of

Hanalei, Hawaii (Fig. 1). A 1/3 arc-second1 DEM of Hanalei, Hawaii referenced to mean high water (MHW) was carefully developed and evaluated. The DEM will be used as input for the Method of Splitting Tsunami (MOST) model

developed by Pacific Marine Environmental Laboratory (PMEL) NOAA Center for Tsunami Research (HUhttp://nctr.

pmel.noaa.gov/UH) to simulate tsunami generation, propagation and inundation. The MHW DEM was generated from

diverse digital datasets in the region (grid boundary and sources shown in Fig. 3) for tsunami inundation modeling, 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 DEM.

Figure 1. Shaded relief image of the Hanalei, Hawaii DEM. Contour intervals for bathymetry are 100 meters and 200 meters for topography.

1. The Hanalei, Hawaii DEM was 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 Hanalei, Hawaii, (22° 12′ 24′′ N, 159°

30′ 3′′ W) 1/3 arc-second of latitude is equivalent to 10.25 meters; 1/3 arc-second of longitude equals 9.55 meters.
Carignan et al., 2012

2. Study Area

The Hanalei DEM covers the northern coast of the island of Kauai, the northern most island of the main

Hawaiian Island Chain (Fig. 2). Hawaii is at risk from tsunamis caused by both distant and local sources. While most

tsunamis that affect Hawaii originate from distant areas where tectonic plates collide (subduction zones), such as

Alaska’s Aleutian Island chain, Japan, and the west coast of South America, regional shallow undersea earthquakes

or landslides can generate local tsunamis. What poses the most danger for residents is the shorter warning time for

locally generated tsunamis, from hours to minutes notice.

Figure 2. Map of the Hawaiian Island Chain and the location of the Hanalei, Hawaii DEM boundary, shown as red box.

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Digital Elevation Model of Hanalei, Hawaii

3. Methodology

The Hanalei MHW 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 Center use of SIFT to provide real-time tsunami forecasts in an

operational environment. The best available bathymetric and topographic digital data were obtained by NGDC and

shifted to common horizontal and vertical datums: North American Datum of 19832 (NAD 83) and MHW, for modeling of maximum flooding. Data were gathered in an area slightly larger (~5%) than the DEM extents. This data “buffer” ensures that gridding occurs across rather than along the DEM boundaries to prevent edge effects. Data processing

and evaluation, and DEM assembly and assessment are described in the following subsections.

Table 1. PMEL specifications for the 1/3 arc-second Hanalei, Hawaii DEM. 

Grid Area Hanalei, Hawaii

Coverage Area 159.09o to 159.91o W; 22.09o to 22.66o N

Coordinate System Geographic decimal degrees

Horizontal Datum World Geodetic System of 1984 (WGS 84)

Vertical Datum Mean high water (MHW)

Vertical Units Meters

Cell Size 1/3 arc-second

Grid Format ESRI ASCII raster 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 DEMs. 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. 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. These DEMs are 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 DEMs, WGS 84 and NAD 83 geographic are identical and may be used

interchangeably.

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Carignan et al., 2012

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 institutions including: NGDC; NOAA’s National Ocean Service (NOS), Office

of Coast Survey (OCS), Center for Coastal Monitoring and Assessment (CCMA); Coastal Services Center (CSC), and

Pacific Services Center (PSC); the County of Kauai Information Technology Division; the Federal Emergency Management Agency (FEMA); the U.S. Army Engineer Joint Airborne Lidar Bathymetry Technical Center of Expertise

(JALBTCX); and the U.S. Geological Survey (USGS). Safe Software’s FME data translation tool package was used to

shift datasets to NAD 83 geographic horizontal datum and to convert them into ESRI ArcGIS shapefiles3. The shapefiles were then displayed with ArcGIS and Applied Imagery’s Quick Terrain Modeler (QT Modeler) to assess data

quality and manually edit datasets. Vertical datum transformations to MHW were accomplished using NOAA’s tide

station information. ESRI’s online World 2D imagery was used to analyze and modify data. QT Modeler, Gnuplot and

Interactive Visualization System’s Fledermaus software were used to evaluate processing and gridding techniques.

Figure 3. Source and coverage of datasets used in building the Hanalei, Hawaii DEM.

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

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Digital Elevation Model of Hanalei, Hawaii

3.1.1 Coastline

Coastline datasets of the Hanalei, Hawaii region were obtained from NOAA’s OCS as Electronic Navigational Charts (ENCs)4

, and Center for Coastal Monitoring and Assessment (CCMA) Biogeography division. Comparisons between the two showed the CCMA coastline more consistent with ESRI’s World 2D imagery, Google Earth and

IKONOS imagery (Table 2; Fig. 4). 

Table 2. Shoreline dataset used in building the Hanalei, Hawaii DEM.

Source Year Data Type Spatial 

Resolution

Original Horizontal 

Datum/Coordinate 

System

Original 

Vertical 

Datum

URL

CCMA 2004 to

2006

Vector shoreline 1:6,000 NAD 83 UTM Zone

4 North (meters) Unknown

http://ccma.nos.noaa.gov/

products/biogeography/hawaii_

cd_07/welcome.html

Figure 4. Comparison of ENC 

MHW shoreline and CCMA

coastline

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/]

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Carignan et al., 2012

The CCMA Kauai shoreline dataset was downloaded from the CCMA Biodiversity web page in shapefile

format and transformed to NAD 83 geographic using ArcCatalog. The data was derived from IKONOS and Quickbird

Satellite Imagery from 2004 to 2006. In mapping the coral reef habitats of the Main Eight Hawaiian Islands by visual

interpretation and manual delineation of IKONOS and Quick Bird satellite imagery, this shapefile was created from

the shoreline digitized during this process.

The CCMA coastline was clipped to 0.05 degrees larger than the Hanalei, Hawaii DEM boundary. Piers and

docks within Hanalei, Hawaii were deleted from the coastline. The coastline was further modified based on Google 

Earth imagery to reflect the most current coastal morphology. An xyz file of the “combined coastline” with points

every 10 meters was generated using NGDC’s GEODAS software for use in creating a bathymetric surface (see Section 3.3.2).

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Digital Elevation Model of Hanalei, Hawaii

3.1.2 Bathymetry

Bathymetric datasets used in the compilation of the Hanalei, Hawaii DEM included: NGDC multibeam

swath sonar surveys, U.S. Army Engineer Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) SHOALS lidar, and NOAA RNC chart soundings (Table 3; Fig. 3). NOS hydrographic surveys were reviewed

but not used as newer data overlapped the surveys or due to the age of the survey. Datasets were originally horizontally

referenced to WGS 84 geographic. The data are vertically referenced to mean lower low water (MLLW) or mean sea

level (MSL).

Table 3. Bathymetric datasets used in compiling the Hanalei, Hawaii DEM.

Source Year Data Type Spatial Resolution

Original Horizontal 

Datum/Coordinate 

System

Original Vertical 

Datum URL

JALBTCX

SHOALS 1999 Hydrographiclidar survey ~ 5 to 10 meters WGS 84 geographic MLLW

http://shoals.sam.

usace.army.mil/

hawaii/pages/Hawaii_Data.htm

NGDC

1995

to

2010

Multibeam swath

sonar surveys

Raw sonar files

gridded to

1 arc-second

WGS 84 geographic Assumed

MSL (meters)

http://www.ngdc.

noaa.gov/mgg/bathymetry/multibeam.

html

NOAA RNC 2008

Digitized NOAA

nautical chart

soundings

10 meters WGS 84 geographic MLLW (meters) http://nauticalcharts.

noaa.gov/mcd/enc/

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Carignan et al., 2012

1) U.S. Army Engineer Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) 

hydrographic lidar surveys

JALBTCX conducted high-resolution hydrographic lidar surveys around Kauai in 1999 and 2000 (Table

4; Fig. 5). These surveys were originally referenced to WGS 84 geographic and MLLW vertical datum (meters). The resolution of the surveys range from roughly 5 to 10 meters and the depths range from -1.1 to -11.3

meters at MHW.

Table 4. JALBTCX / SHOALS hydrographic surveys used in compiling the Hanalei, Hawaii DEM.

Survey name Date Resolution Original Horizontal Datum Original Vertical 

Datum

Kauai 3 1999 ~ 5 to 10 meters WGS 84 geographic MLLW

Kauai 4 1999 ~ 5 to 10 meters WGS 84 geographic MLLW

Kauai 5 1999 ~ 5 to 10 meters WGS 84 geographic MLLW

Kauai 6 1999 ~ 5 to 10 meters WGS 84 geographic MLLW

Figure 5. Spatial coverage of the JALBTCX / SHOALS hydrographic lidar surveys used in developing the Hanalei DEM. Red solid line denotes 

the DEM boundary and the green dashed line denotes extent of data (See Sec. 3.0).

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Digital Elevation Model of Hanalei, Hawaii

2) NOAA NGDC multibeam database surveys

Twenty-four multibeam swath sonar surveys (Table 5, Fig. 6) are available from the NGDC multibeam

sonar bathymetry database for the Hanalei DEM region. This database is comprised of the original swath

sonar files of surveys conducted mostly by the U.S. academic fleet. Two of these surveys were not used in

building the DEM due to poor quality of returns throughout the survey. Surveys are referenced to a horizontal datum of WGS 84 geographic and an undefined vertical datum, assumed to be essentially MSL.

The downloaded data were gridded to 1 arc-second resolution using MB-System5. Further editing of the

gridded data was done using QT Modeler and clipped to JALBTCX SHOALS bathymetric lidar surveys.

Two surveys, KRUS05RR and KM0326 required individual swath editing which was done using MB-system

swath editing tools (Fig. 7).

Table 5. Multibeam swath sonar surveys used in compiling the Hanalei, Hawaii DEM.

Cruise ID Collecting Institution Year Ship

AHI-06-09 National Oceanic and Atmospheric Administration (NOAA/NMFS) 2006 Ahi

AVON06MV University of California, Scripps Institution of Oceanography (UC/SIO) 1999 Melville

AVON07MV UC/SIO 1999 Melville

AVOM08MV UC/SIO 1999 Melville

CNTL12RR UC/SIO 2003 Roger Revelle

COOK23MV UC/SIO 2002 Melville

DRFT15RR UC/SIO 2002 Roger Revelle

EW9508 Columbia University, Lamont-Doherty Earth Observatory (CU/LDEO) 1995 Maurice Ewing

HI-05-05 NOAA/NMFS 2005 Hi’ialakai

HI-06-09 NOAA/NMFS 2006 Hi’ialakai

HLY10TC Columbia University, Lamont-Doherty Earth Observatory (CU/LDEO) /

Rolling Deck to Repository (R2R) Program 2010 Healy

KIWI03RR UC/SIO 1997 Roger Revelle

KM0326 University of Hawaii (UH) / Rolling Deck to Repository (R2R) Program 2003 Kilo Moana

KM0622 UH/R2R 2006 Kilo Moana

KM0710 UH/R2R 2007 Kilo Moana

KM0810 UH/R2R 2008 Kilo Moana

KRUS01RR UC/SIO 2004 Roger Revelle

KRUS05RR UC/SIO 2004 Roger Revelle

LFEX01MV UC/SIO 2004 Melville

NBP0304 CU/LDEO 2003 Nathaniel B. Palmer

NBP0304B CU/LDEO 2003 Nathaniel B. Palmer

VANC33MV UC/SIO 2004 Melville

5. MB-System is an open source software package for the processing and display of bathymetry and backscatter imagery data derived from

multibeam, interferometry, and sidescan sonars. The source code for MB-System is freely available (for free) by anonymous ftp (including “point

and click” access through these web pages). A complete description is provided in web pages accessed through the web site. MB-System was

originally developed at the Lamont-Doherty Earth Observatory of Columbia University (L-DEO) and is now a collaborative effort between

the Monterey Bay Aquarium Research Institute (MBARI) and L-DEO. The National Science Foundation has provided the primary support for

MB-System development since 1993. The Packard Foundation has provided significant support through MBARI since 1998. Additional support

has derived from SeaBeam Instruments (1994-1997), NOAA (2002-2004), and others. [Extracted from MB-System web site; http://www.ldeo.

columbia.edu/res/pi/MB-System/]

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Carignan et al., 2012

Figure 6. Spatial coverage of the NGDC multibeam survey data available in the Hanalei, Hawaii region.

Figure 7. An example of swath edits 

made in multibeam survey KRUS05RR. 

Red arrows point to areas where returns 

were suspect and removed before regridding.

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Digital Elevation Model of Hanalei, Hawaii

3) Digitized Nautical Chart soundings

Three NOAA Nautical charts are available from OCS in Raster Nautical Chart (RNC)6 format within

the Hanalei DEM boundary (Table 6). Sounding data from chart #19385 were digitized with depth values

referenced to MLLW. The points were extrapolated to 10 meters apart using GEODAS and depth values were

transformed to MHW using a constant value and converted to xyz format for use in creating a bathymetric

pre-surface and in the final DEM. Figure 8 shows the coverage of the digitized soundings within the Hanalei

Bay region.

Table 6. Nautical charts available in the Hanalei, Hawaii region.

Chart Title Format Edition Issue Date Scale

19380 Oahu to Niihau RNC 15 2003 1: 247,482

19381 Island of Kauai ENC and RNC 3 2010 1:80,000

19385 North Coast of Kauai - Haena Point to Kepuhi Point RNC 8 2003 1:20,000

Figure 8. Spatial data coverage of digitized RNC soundings.

6. The Office of Coast Survey (OCS) produces NOAA Electronic Navigational Charts (NOAA ENC®s) 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/]

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Carignan et al., 2012

3.1.3 Topography

Topographic datasets in the Hanalei, Hawaii region were obtained from: USGS, NOAA’s Pacific Services

Center (PSC), and the State of Hawaii Civil Defense (Table 7; Fig. 3). Ifsar data in DTM format for the entire island

was available for use in building the Hanalei DEM but was not used due to the significant number of patches of interpolated data generated in areas of no data.

Table 7. Topographic datasets used in compiling the Hanalei, Hawaii DEM.

Source Year Data Type Spatial Resolution Original Horizontal Datum/Coordinate System

Original Vertical 

Datum URL

USGS NED 2000 Topographic DEMs 1/3 arc-second grid NAD 83 geographic NAVD 88 http://seamless.

usgs.gov/

State of

Hawaii Civil

Defense /

FEMA

2006 Lidar ~ 3 feet NAD 83 State Plane HI

Zone 4 FIPS 5104 (feet) Local tidal

JALBTCX /

PSC 2007 Lidar

1 meter data downloaded as 5 meter

averaged grid

NAD 83 geographic Mean Sea Level

4) U.S. Geological Survey National Elevation Dataset topography

USGS National Elevation Dataset (NED) provides complete 1/3 arc-second coverage of the Hanalei, Hawaii region7

. The dataset is available for download as raster DEMs in NAD 83 geographic horizontal datum

and NAVD 88 (meters) vertical datum. The bare-earth elevations have a vertical accuracy of +/- 7 to 15 meters depending on source data resolution (see the USGS Seamless website for specific source information).

The dataset was derived from USGS quadrangle maps and aerial photographs based on topographic surveys.

The USGS NED 1/3 arc-second DEM data were downloaded from the USGS website. ArcCatalog tools

were used to clip the NED DEMs to the combined coastline. FME was used to convert the rasters to xyz

format. Other higher resolution data were available to replace the NED data along the coast.

7. 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 California. The dataset provides seamless

coverage of the United States, HI, CA, 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 Alaska, which is NAD 27. The vertical datum is NAVD 88, except for Alaska,

which is NGVD 29. 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; http://ned.usgs.gov/]

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Digital Elevation Model of Hanalei, Hawaii

5) State of Hawaii Civil Defense / FEMA Lidar

Pacific Services Center (PSC) provided NGDC with the State of Hawaii Civil Defense topographic lidar

dataset. The lidar was flown in 2006 in support of hurricane study for the Hawaiian Islands and was specified

to include coverage from the coastline up to the 10 meter contour elevation with an average point spacing of

3 feet. The data, in .las format 1.0 and ground last return (classification code 2) were projected to NAD 83

State Plane Hawaii Zone 4 FIPS 5104 (feet), and reference to local tidal datum, assumed to be local mean sea

level. Data were converted to xyz format and transformed to NAD 83 geographic using FME.

6) JALBTCX Hawaii lidar

PSC provided lidar data from 2007 of the northern shoreline of Kauai. The purpose of the 2007 Hawaii

survey, in general, was to collect both bathymetric and topographic lidar along the northern coastline of the

Hawaiian Islands. Topographic data were required between the zero and 15 meter contours, nominal, for the

northern coastline of the islands of Hawaii (Big Island), Kauai, Maui, Molokai, and Oahu. The data were

to be collected from the land water interface seaward to a depth of 40 meters or laser extinction, whichever

comes first. These data were collected for Hawaii State Civil Defense for tsunami mapping purposes. The one

meter lidar data were gridded to 5 meters using an average grid method and referenced to NAD 83 geographic

and mean sea level. 

Figure 9 shows an example of the two lidar datasets and the area surrounding Anahola Bay on the eastern side

of Kauai. The elevation values are very similar. Both data sets required automated clipping to the CCMA coastline to

remove returns from the water.

Figure 9. A comparison of FEMA and JALBTCX lidar at Anahola Bay. Cross section shows majority of elevation values match.

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Carignan et al., 2012

3.2 Establishing Common Datums

3.2.1 Vertical datum transformations

Datasets used in the compilation and evaluation of the Hanalei DEM were originally referenced to a number

of vertical datums including: Local tidal datum, MLLW, MSL, and NAVD 88. All datasets were transformed to MHW

using a constant value based on the average of the tide stations on Kauai. Locations of the tide stations are shown in

Figure 16.

7) Bathymetric data

The multibeam surveys, the JALBTCX SHOALS data, and the nautical chart soundings were transformed from MSL, and MLLW to MHW, using a constant value. The average of the relationships between

the various vertical datums and MHW based on two tide stations in the DEM region are listed in Table 8.

8) Topographic data

The NED DEM and the lidar data were originally referenced to NAVD 88, local tidal datum, or mean sea

level. For this DEM, local tidal datum and mean sea level were assumed to be equal. As NAVD 88 does not

exist on the Hawaiian Islands data referenced to NAVD 88 was also treated as mean sea level. Transformations from MSL to MHW were done using a constant value based on an average value of the two tide stations

(Table 8).

Table 8. Relationships between MHW and other vertical datums in meters within the Hanalei, Hawaii DEM region.

Nawiliwili Harbor Port Allen, Hanapepe Bay

MHHW 0.558 0.561

MHW 0.434 0.439

MTL 0.247 0.249

MSL 0.252 0.254

MLW 0.061 0.06

NAVD 88 n/a n/a

MLLW 0 0

Difference in datums Difference in datums Average of values

MSL to MHW -0.182 -0.185 -0.1835

MLLW to MHW -0.434 -0.439 -0.4365

3.2.2 Horizontal datum transformations

Datasets used in compiling the Hanalei DEM were originally referenced to: NAD 83 and WGS 84 geographic; NAD 83 UTM Zone 4 North (meters); and NAD 83 State Plane Hawaii Zone 4 FIPS 5104 (feet) horizontal datums.

The relationships and transformational equations between the geographic horizontal datums are well established and

transformation to NAD 83 geographic were done using FME or ArcGIS software.

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Digital Elevation Model of Hanalei, Hawaii

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

ESRI ArcMap and QT Modeler for inter-dataset consistency. 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:

•	 Data values over the water in topographic datasets. Data required automated clipping to the combined

coastline or manual editing.

•	 Inconsistent, overlapping bathymetric datasets. Lower-resolution datasets were clipped to higherresolution data and all datasets were weighted based on quality and age in gridding process.

3.3.2 Smoothing of bathymetric data

In order to reduce the effect of artifacts in the form of lines of “pimples” in the 1/3 arc-second DEM due to

variable resolution datasets, and to provide effective interpolation into the coastal zone, a 1 arc-second-spacing “presurface” or grid was generated using GMT8

.

The JALBTCX SHOALS surveys, RNC soundings, and NGDC multibeam swath sonar bathymetry data

were combined into a single file. Points extracted every 10 meters from the combined coastline were also included and

assigned elevation values of zero meters to ensure that the offshore elevations remained negative. These point data

were then smoothed using the GMT tool “blockmedian” onto a 1 arc-second grid. The GMT tool “surface” was then

applied to interpolate values for cells without data values. The GMT grid created by “surface” was converted into an

ESRI Arc ASCII grid file using the MB-System tool “mbm_grd2arc”. Conversion of this Arc ASCII grid file into an

Arc raster permitted clipping of the grid with the combined coastline (to eliminate data interpolation into land areas).

The resulting surface was compared with original soundings to ensure grid accuracy, converted to an xyz file

for use in the final gridding process (see Table 9). The statistical analysis of the differences between the 1 arc-second

bathymetric surface and one multibeam survey showed that the majority of the soundings are in good agreement with

the bathymetric surface (Fig. 10).

8. GMT is an open source collection of ~60 tools for manipulating geographic and Cartesian data sets (including filtering, trend fitting, gridding,

projecting, etc.) and producing Encapsulated PostScript File (EPS) illustrations ranging from simple x-y plots via contour maps to artificially

illuminated surfaces and 3-D perspective views. GMT supports ~30 map projections and transformations and comes with support data such as

GSHHS coastlines, rivers, and political boundaries. GMT is developed and maintained by Paul Wessel and Walter H. F. Smith with help from a

global set of volunteers, and is supported by the National Science Foundation. It is released under the GNU General Public License. [Extracted from

GMT web site; http://gmt.soest.hawaii.edu/]

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Carignan et al., 2012

Figure 10. Histgram of differences between the 1 arc-second bathymetric surface and multibeam survey AVON07MV.

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Digital Elevation Model of Hanalei, Hawaii

3.3.3 Building the 1/3 arc-second MHW DEM

MB-System was used to create 1/3 arc-second DEM of Hanalei, Hawaii. The MB-System tool “mbgrid” applied a tight spline tension to the xyz data, and interpolated values for cells without data. The data hierarchy used in the

“mbgrid” gridding algorithm, as relative gridding weights, is listed in Table 9. Greatest weight was given to the RNC

soundings and the bathymetric surface. Least weight was given to the deep water NGDC multibeam and NED DEM.

Table 9. Data hierarchy used to assign gridding weight in MB-System

Dataset Relative Gridding Weight

RNC soundings 100

Bathymetric ‘pre-surfaced’ data 100

FEMA lidar 10

JALBTCX / PSC lidar 10

JALBTCX / SHOALS surveys 10

Combined coastline 10

USGS NED 1/3 DEM 1

NGDC multibeam data 1

3.4 Quality Assessment of the DEM

3.4.1 Horizontal accuracy

The horizontal accuracy of topographic and bathymetric features in the Hanalei, Hawaii DEM are dependent

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

have an estimated horizontal accuracy of less than 10 meters, based on the documented accuracy of the dataset. Lidar

datasets have an accuracy of less than one meter. Gridded multibeam survey data have a positional accuracy of 10

meters. More recent JALBTCX / SHOALS bathymetric lidar data have accuracy of + / - 3 meters.

3.4.2 Vertical accuracy

Vertical accuracy of elevation values for the Hanalei DEM are also highly dependent upon the source datasets contributing to grid cell values. Topographic datasets have vertical accuracies of less than 1 meter, derived

from FEMA and JALBTCX / PSC lidar data, and the NED topographic data has an estimated vertical accuracy of

10 meters. Bathymetric values, derived from single and multibeam sounding measurements, are 0.3 meters in 0 to 20

meters of water, 1.0 meters in 20 to 100 meters of water, and 1% of the water depth in 100 meters of water. Gridding

interpolation to determine bathymetric values between sparse data degrades the vertical accuracy of elevations in deep

water to about 5% of water depth. JALBTCX / SHOALS data have a vertical accuracy of 0.3 meter.

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Carignan et al., 2012

3.4.3 Slope map, 3-D perspective and data contribution plot

ESRI ArcCatalog was used to generate a slope grid from the 1/3 arc-second Hanalei DEM to allow for visual

inspection and identification of artificial slopes along boundaries between datasets (Fig. 11). The DEM was transformed to NAD 83 UTM Zone 4 North coordinates (horizontal units in meters) in ArcCatalog for derivation of the

slope grid; equivalent horizontal and vertical units are required for effective slope analysis. Dark areas indicate steeper

slopes while lighter areas indicate low slope.

Figure 11. Slope map of the Hanalei DEM.

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Digital Elevation Model of Hanalei, Hawaii

A high-resolution perspective image was generated using Fledermaus, providing three-dimensional viewing of the DEM (Fig. 12). Analysis of preliminary grids revealed suspect data points, which were corrected before

recompiling the DEM.

Figure 12. A perspective image of the Hanalei DEM. View is from the northeast and vertical exaggeration is 2x.

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Carignan et al., 2012

3.4.4 MHW DEM comparison with source data files

To ensure grid accuracy, the 1/3 arc-second Hanalei DEM was compared to select source data files. Large

differences between the NBP0304B multibeam survey data and the Hanalei DEM occur where surveys overlap and in

areas of rough terrain (Fig. 13). 

A random sample of data files were used for comparing the high-resolution lidar topographic files to the

DEM. Figures 14 and 15 show histograms of the differences between the DEM and two sample files of the lidar datasets. In both datasets, the largest differences between the lidar and the Hanalei DEM were located in areas of dense

vegetation.

Figure 13. Histogram of the differences between the multibeam survey NBP0304B and the Hanalei DEM.

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Digital Elevation Model of Hanalei, Hawaii

Figure 14. Histogram of differences between a sample set of JALBTCX / PSC lidar data and the Hanalei DEM.

Figure 15. Histogram of differences between a sample set of FEMA lidar data and the Hanalei DEM.

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Carignan et al., 2012

3.4.5 Comparison with National Geodetic Survey geodetic monuments

The elevations of 118 geodetic monuments were extracted from the NOAA NGS web site (http://www.ngs.

noaa.gov/) in shapefile format (see Fig. 16 for monument locations). Shapefile attributes give positions in NAD 83

geographic (typically sub-mm accuracy) and elevations in NAVD 88 (in meters). Elevations were compared to the

Hanalei, Hawaii DEM. The largest difference, over 500 meters, is due to an error in either monument location or elevation. The monument elevation is recorded as 1151 meters in an area that is roughly 620 meters. Excluding this error,

differences between the DEM and the monument elevations range from -6.05 to 40.78 meters, over 80% of which are

within ± 5 meters (Fig. 17).

Figure 16. Location of NGS monuments within the Hanalei DEM boundary, in red. Tide stations are labeled.

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Digital Elevation Model of Hanalei, Hawaii

Figure 17. Histogram of the differences between the NGS monument elevations and the Hanalei DEM.

4. Summary and Conclusions

An integrated bathymetric–topographic DEM of Hanalei, Hawaii with cell size of 1/3 arc-second, vertically

referenced to MHW 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, Fledermaus, FME, GDAL, GMT, Gnuplot, GEODAS, Quick Terrain Modeler,

MB-System, and VDatum software.

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

•	 Conduct bathymetric–topographic lidar surveys within Hanalei Bay, Hawaii.

•	 Conduct higher resolution bathymetric surveys for coral reef areas.

5. Acknowledgments

The creation of the DEM was funded by NOAA Center for Tsunami Research at PMEL. The authors thank

Nazila Merati and Vasily Titov (PMEL), Jamie Carter (Pacific Service Center), Craig Tasaka (State of Hawaii, Office

of Planning), Garrett Johnson (County of Kauai - IT Division), and Carter Romero (County of Hawaii - National Flood

Insurance Program).

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6. References

Electronic Navigational Chart #19381, 3rd Edition, 2010. Island of Kauai. Scale 1:80,000. U.S. Department of

Commerce, NOAA, National Ocean Service, Coast Survey.

Raster Nautical Chart #19380, 15th Edition, 2003. Oahu to Niihau. Scale 1:247,482. U.S. Department of Commerce,

NOAA, National Ocean Service, Coast Survey.

Raster Nautical Chart #19385, 8th Edition, 2003. North Coast of Kauai - Haena Point to Kepuhi Point. Scale 1:20,000.

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

7. Data Processing Software

ArcGIS v. 10 – developed and licensed by ESRI, Redlands, California, http://www.esri.com/

ESRI World Imagery (ESRI_Imagery_World_2D) – ESRI ArcGIS Resource Centers http://resources.esri.com/

arcgisonlineservices/

FME 2010 GB – Feature Manipulation Engine, developed and licensed by Safe Software, Vancouver, BC, Canada,

HUhttp://www.safe.com/UH

Fledermaus v. 7.0.0 – developed and licensed by Interactive Visualization Systems (IVS 3D), Fredericton, New

Brunswick, Canada, http://www.ivs3d.com/

GDAL v. 1.7.1 – Geographic Data Abstraction Library is a translator library maintained by Frank Warmerdam, http://

www.gdal.org/

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

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

GMT v. 4.3.4 – Generic Mapping Tools, freeware developed and maintained by Paul Wessel and Walter Smith, funded

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

Gnuplot v. 4.2 – shareware developed and maintained by Thomas Williams, Colin Kelley, Russell Lang, Dave Kotz,

John Campbell, Gershon Elber, Alexander Woo http://www.gnuplot.info/

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

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

Persistence of Vision Pty. Ltd (POV Ray) v. 3.6 – Persistence of VisionTM Raytracer. Persistence of Vision Pty.,

Williamstown, Victoria, Australia, http://www.povray.org/

Quick Terrain Modeler v. 7.0.0 – Lidar processing software developed by John Hopkins University’s Applied Physics

Laboratory (APL) and maintained and licensed by Applied Imagery, HUhttp://www.appliedimagery.com/UH

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Digital Elevation Model of Hanalei, Hawaii

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