Digital Elevation Model for Port Orford, Oregon:

Procedures, Data Sources and Analysis

Prepared for the Pacific Marine Environmental Laboratory (PMEL) NOAA Center for Tsunami 

Research by the NOAA National Geophysical Data Center (NGDC)

March 14, 2008

Taylor, L.A., B.W. Eakins, K.S. Carignan, R.R. Warnken, T. Sazonova, and D.C. Schoolcraft

NOAA, National Geophysical Data Center, Boulder, Colorado

Corresponding author 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/
2 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

CONTENTS

1. Introduction..............................................................................................................................................4

2. Study Area ...............................................................................................................................................5

3. Methodology............................................................................................................................................5

3.1 Data Sources and Processing...........................................................................................................6

3.1.1 Shoreline ....................................................................................................................7

3.1.2 Bathymetry.................................................................................................................9

3.1.3 Topography..............................................................................................................20

3.2 Establishing Common Datums......................................................................................................25

3.2.1 Vertical datum transformations..............................................................................25

3.2.2 Horizontal datum transformations..........................................................................25

3.3 Digital Elevation Model Development.........................................................................................25

3.3.1 Verifying consistency between datasets ................................................................25

3.3.2 Smoothing of bathymetric data...............................................................................26

3.3.3 Gridding the data with MB-System .......................................................................26

3.4 Quality Assessment of the DEM...................................................................................................27

3.4.1 Horizontal accuracy.................................................................................................27

3.4.2 Vertical accuracy .....................................................................................................27

3.4.3 Slope maps and 3-D perspectives...........................................................................28

3.4.4 Comparison with source data files .........................................................................29

3.4.5 Comparison with NGS geodetic monuments ........................................................30

4. Summary and Conclusions ...................................................................................................................32

5. Acknowledgments.................................................................................................................................32

6. References..............................................................................................................................................32

7. Data Processing Software .....................................................................................................................33

LIST OF FIGURES

Figure 1. Shaded-relief image of the Port Orford, Oregon DEM .................................................................4

Figure 2. Google Earth satellite image of the Oregon coast .........................................................................5

Figure 3. Source and coverage of datasets used to compile the Port Orford DEM.....................................6

Figure 4. Digital coastline datasets used in developing a ‘derived coastline’ for the Port Orford 

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

Figure 5. Spatial coverage of bathymetric datasets used to compile the Port Orford DEM .....................10

Figure 6. Digital NOS hydrographic survey coverage in the Port Orford region......................................12

Figure 7. Digital USACE hydrographic survey coverage in the Port Orford region.................................14

Figure 8. Spatial coverage of digital multibeam sonar surveys from NGDC multibeam 

database used in the Port Orford region................................................................................15

Figure 9. QT Modeler image of data spikes in multibeam survey Tran2sou.............................................16

Figure 10. QT Modeler image of multibeam survey LWAD99MV showing center beam noise 

errors of up to 50 meters........................................................................................................16

Figure 11. QT Modeler image of cross section comparing gridded bathymetric surfaces..........................17

Figure 12. Images of gridded multibeam surveys provided by Oregon Dept. of Fish and 

Wildlife/Marine Program.......................................................................................................18

Figure 13. Spatial coverage of the OCS chart sounding data used to compile the Port Orford 

DEM........................................................................................................................................19

Figure 14. Spatial coverage of topographic datasets used in the Port Orford DEM....................................20

Figure 15. NED topographic data at Coos Bay..............................................................................................21

Figure 16. Spatial coverage of the CSC topographic LiDAR within the Port Orford DEM boundary......22

Figure 17. Comparison of CSC LiDAR data coverage and NASA Geocover2000 shortwavelength infrared image.....................................................................................................23

Figure 18. Location and aerial photos of the four NGDC digitized jetties ..................................................24

Figure 19. Histogram of the differences between NOS hydrographic survey H04891 and the 1 

arc-second pre-surfaced bathymetric grid.............................................................................26
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 3

Figure 20. Slope map of the Port Orford DEM.............................................................................................28

Figure 21. Perspective view of the Port Orford DEM ..................................................................................29

Figure 22. Histogram of the differences between USACE hydrographic survey........................................29

Figure 23. Histogram of the differences between NGS monuments and Port Orford DEM ......................30

Figure 24. Location of NGS geodetic monuments and the NOAA Port Orford tide station ......................31

LIST OF TABLES

Table 1. PMEL specifications for the Port Orford, Oregon DEM ..............................................................5

Table 2. Shoreline datasets available in the Port Orford, Oregon region ...................................................7

Table 3. Raster nautical charts available in the Port Orford, Oregon region..............................................8

Table 4. Bathymetric datasets used in compiling the Port Orford DEM ....................................................9

Table 5. Digital NOS hydrographic surveys used in compiling the Port Orford DEM ...........................11

Table 6. USACE surveys used in compiling the Port Orford DEM..........................................................13

Table 7. Multibeam surveys from NGDC database used in compiling the Port Orford DEM................15

Table 8. Topographic datasets used in compiling the Port Orford DEM..................................................20

Table 9. Summary of True Color and Short-Wavelength InfraRed (SWIR) satellite imagery 

representing surface features .................................................................................................23

Table 10. Relationship between Mean High Water and other vertical datums in the Port Orford 

region.......................................................................................................................................25

Table 11. Data hierarchy used to assign gridding weight in MB-System...................................................26
4 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

Digital Elevation Model for Port Orford, Oregon:

Procedures, Data Sources and Analysis

1. INTRODUCTION

The National Geophysical Data Center (NGDC), an office of the National Oceanic and Atmospheric 

Administration (NOAA), has developed an integrated bathymetric–topographic digital elevation model (DEM) of 

Port Orford, Oregon (Fig. 1) for the Pacific Marine Environmental Laboratory (PMEL) NOAA Center for Tsunami 

Research (http://nctr.pmel.noaa.gov/). The 1/3 arc-second1 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) and 

will be used for tsunami inundation modeling, as part of the tsunami forecast system SIFT (Short-term Inundation 

Forecasting for Tsunamis) currently being developed by PMEL for the NOAA Tsunami Warning Centers. This 

report provides a summary of the data sources and methodology used in developing the Port Orford DEM.

Figure 1. Shaded-relief image of the Port Orford, Oregon DEM. Contour 

interval is 50 meters in water and 100 meters on land. Image is in Mercator 

projection.

 1. The Port Orford 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 Port Orford, Oregon (42°44.6′ N, 

124°29.8′ W) 1/3 arc-second of latitude is equivalent to 10.3 meters; 1/3 arc-second of longitude equals 7.6 meters.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 5

2. STUDY AREA

The Port Orford DEM covers the coastal region surrounding the town of Port Orford, Oregon from Umpqua River in 

the north to the town of Ophir in the south and includes the communities of Port Orford, Langlois, Bandon, 

Charleston, Coos Bay, North Bend, and Winchester Bay (Fig. 2). Encompassing a portion of the Oregon Dunes 

National Recreation Area and the Oregon Islands National Wildlife Refuge, the DEM includes many offshore rocks, 

small islands, reefs, and shoreline cliffs. The region is home to many species of coastal bird and animal life which 

provide recreation and educational opportunities. The town of Port Orford is located south of Cape Blanco, the 

westernmost point of the Oregon coast, and has a population of approximately 1,100. 

Figure 2. Google Earth satellite image of the Oregon coast. Port Orford DEM 

boundary shown in red. Image is in Mercator projection.

3. METHODOLOGY

The Port Orford, Oregon DEM was developed to meet PMEL specifications (Table 1), based on input 

requirements for the MOST inundation model. The best available digital data were obtained by NGDC and shifted 

to common horizontal and vertical datums: World Geodetic System 1984 (WGS84) and Mean High Water (MHW), 

for modeling of “worst-case scenario” flooding, respectively. Data processing and evaluation, and DEM assembly 

and assessment are described in the following subsections.

Table 1: PMEL specifications for the Port Orford, Oregon DEM.

Grid Area Port Orford, Oregon

Coverage Area 124.13o to 124.97o W; 42.53o to 43.73o N

Coordinate System Geographic decimal degrees

Horizontal Datum World Geodetic System 1984 (WGS84)

Vertical Datum Mean High Water (MHW)

Vertical Units Meters

Grid Spacing 1/3 arc-second

Grid Format ESRI Arc ASCII grid
6 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

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 including: NOAA’s National Ocean Service (NOS), Office of Coast Survey (OCS) and Coastal 

Services Center (CSC); the U.S. Geological Survey (USGS); the U.S. Army Corps of Engineers (USACE); and the 

Oregon Department of Fish and Wildlife/Marine Resource Program (ORDFW). Safe Software’s 

(http://www.safe.com/) FME data translation tool package was used to shift datasets to WGS84 horizontal datum 

and to convert them into ESRI (http://www.esri.com/) ArcGIS shape files. The shape files 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 Port Orford tide station. Applied Imagery’s Quick 

Terrain Modeler software (http://www.appliedimagery.com/) was used to evaluate processing and gridding 

techniques.

Figure 3. Source and coverage of datasets 

used to compile the Port Orford DEM.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 7

3.1.1 Shoreline

Coastline datasets of the Port Orford region were obtained from NOAA’s Office of Coast Survey as Electronic 

Navigational Charts (ENCs) and Raster Nautical Charts (RNCs); and the Oregon Resources Management Task 

Force (ORMTF). Of these datasets, only the RNCs were used to derive a coastline for the Port Orford DEM (Table 

2; Fig. 4). Both the ORMTF coastline and the extracted ENC coastline were shifted in different directions up to 100 

meters from topographic datasets and were not used in the Port Orford DEM. The resolution of the ENC coastline 

was also too coarse for use in the DEM. 

Table 2: Shoreline dataset used in the Port Orford DEM.

Source Year Data Type

Spatial 

Resolution

Original Horizontal 

Datum/Coordinate 

System

Original Vertical 

Datum URL

OCS RNC 

derived 

coastline

2007 derived from 

raster data

1:20,000 to 

1:191,730

WGS84 geographic 

(meters) Mean High Water

http://nauticalchar

ts.noaa.gov/mcd/

Raster/Index.htm

1) OCS Raster Nautical Charts

 Six raster nautical charts (RNCs) were available for the Port Orford area (Table 3) and downloaded 

from NOAA’s Office of Coast Survey website (http://nauticalcharts.noaa.gov/mcd/enc/index.htm). The 

RNCs are provided online as georeferenced raster images and cover the entire coastline within the DEM 

boundaries. RNC #18600 was not used as smaller scale raster images were available covering the same 

area. 

Figure 4. RNC datasets used in developing 

a ‘derived coastline’ for the Port Orford 

DEM. Gray hachured regions show where 

manual adjustments to coastline were 

made.
8 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

Table 3: Raster nautical charts available in the Port Orford, Oregon region.

Chart Title Edition Edition Date Scale

18580 Cape Blanco to Yaquina Head 22 2005 1:191,730

18587 Coos Bay 70 2005 1:20,000

18588 Coquille River Entrance 37 2003 1:20,000

18589 Port Orford to Cape Blanco 16 2007 1:40,000

18600 Trinidad Head to Cape Blanco 14 2002 1:196,948

18601 Cape Sebastian to Humbug Mountain 14 2007 1:40,000

A ‘derived coastline’ was generated using ArcGIS Spatial Analyst to extract the coastline from the raster image 

of the nautical chart based on pixel values. The resulting data was then resampled and converted to polylines and 

merged into a single dataset. Further editing of the coastline was done to remove stray line segments in the open 

ocean using ArcMap editing tools. Where the coastline was derived from the low resolution RNC (#18580), 

adjustments to the edited coastline were made to increase the detail by matching the topographic datasets. These 

areas are shown in Figure 4 as hachured polygons. Some manmade features, such as bridges and piers, were 

removed to prevent their inclusion in the DEM. Jetties at Port Orford, Coquille River, Coos Bay, and Umpqua River 

were checked for accuracy against aerial photos, Google Earth images, and CSC LiDAR topography and adjusted to 

ensure representation in the DEM (See Sec. 3.1.3).
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 9

3.1.2 Bathymetry

Bathymetric datasets used in the compilation of the Port Orford DEM include 34 NOS hydrographic surveys, 22

hydrographic channel line surveys from USACE, 7 multibeam sonar swath files downloaded from the NGDC 

multibeam sonar database, two multibeam sonar surveys from the Oregon Dept. of Fish and Wildlife/Marine 

Resources Program (ORDFW), extracted ENC sounding data, and digitized RNC soundings (Table 4; Fig. 5).

Table 4: Bathymetric datasets used in compiling the Port Orford DEM.

Source Year Data Type Spatial Resolution

Original 

Horizontal 

Datum/Coordinate 

System

Original 

Vertical 

Datum

URL

NOS

1889 

to 

1991

Hydrographic 

survey 

soundings

Ranges from 10 m to 

1 km (varies with 

scale of survey, 

depth, traffic, and 

probability of 

obstructions)

NAD27 or 

NAD83

geographic

Mean Lower 

Low Water

http://www.ngdc.noaa

.gov/mgg/bathymetry/

hydro.html

USACE

2006 

to 

2007

Hydrographic 

channel line 

surveys

various, from 3 to 40 

meter point spacing

NAD83 Oregon 

State Plane South 

(feet)

 Mean 

Lower Low 

Water

https://www.nwp.usac

e.army.mil/op/nwh/xy

zcoastal.asp

NGDC 

1998 

to 

2003

Multibeam 

sonar swath 

files

raw MB files gridded 

to 1 arc-second

WGS84 

geographic

assumed 

Mean Sea 

Level

http://www.ngdc.noaa

.gov/mgg/bathymetry/

multibeam.html

ORDFW/Marine 

Resources 

Program

1999 

and 

2000

Multibeam 

sonar surveys 1 to 2 meter grid NAD83 UTM Zone10 meters

Mean Lower 

Low Water

OCS RNCs

2003 

to 

2005

digitized 

soundings from 

RNCs

1:20,000 WGS84 

geographic

Mean Lower 

Low Water

http://nauticalcharts.n

oaa.gov/mcd/Raster/In

dex.htm

OCS ENC 2005

extracted 

soundings from 

ENC

1: 191,730 WGS84 

geographic

Mean Lower 

Low Water

http://chartmaker.ncd.

noaa.gov/MCD/enc/in

dex.htm
10 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

Figure 5. Spatial coverage of bathymetric datasets used to compile the Port Orford DEM.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 11

1) NOS hydrographic survey data

A total of 34 NOS hydrographic surveys conducted between 1889 and 1991 were available for use in 

developing the Port Orford DEM. The hydrographic survey data were originally vertically referenced to 

Mean Lower Low Water (MLLW) and horizontally referenced to either NAD27 or NAD83 datums (Table 

5; Fig. 6).

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

greater point spacing than more recent surveys. All surveys were extracted from NGDC’s online NOS 

hydrographic database (http://www.ngdc.noaa.gov/mgg/bathymetry/hydro.html) referenced to NAD83. The 

data were then converted to WGS84 using FME software, an integrated collection of spatial extract, 

transform, and load tools for data transformation (http://www.safe.com). The surveys were subsequently 

clipped to a polygon 0.05 degree (~5%) larger than the Port Orford DEM area to support data interpolation 

along grid edges.

After converting all NOS survey data to MHW using a constant based on the Port Orford tide station 

(see Section 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 other bathymetric datasets, the derived coastline, and NOS raster nautical charts (RNCs). 

The surveys were clipped to remove soundings that overlap the more recent multibeam surveys and where 

soundings from older surveys have been superseded by more recent NOS surveys.

Table 5: Digital NOS hydrographic surveys used in compiling the Port Orford DEM.

Survey ID Year Scale Original Vertical Datum Original Horizontal Datum

H01946 1889 20,000 MLW NAD27

H04217 1922 40,000 MLLW NAD27

H04218 1922 120,000 MLLW NAD27

H04452 1924 40,000 MLLW NAD27

H04479 1924 40,000 MLLW NAD13

H04487 1925 20,000 MLLW NAD27

H04505 1925 40,000 MLLW NAD27

H04531 1925 120,000 MLLW NAD27

H04503A 1925/26 120,000 MLLW NAD27

H04812 1928 10,000 MLLW NAD27

H04813 1928 20,000 MLLW NAD27

H04814 1928 10,000 MLLW NAD27

H04815 1928 40,000 MLLW NAD27

H04817 1928 20,000 MLLW NAD27

H04819 1928 20,000 MLLW NAD27

H04883 1928 40,000 MLLW NAD27

H04885 1928 20,000 MLLW NAD27

H04886 1928 20,000 MLLW NAD27

H04887 1928 10,000 MLLW NAD27

H04889 1928 120,000 MLLW NAD27

H04890 1928 40,000 MLLW NAD27

H04891 1928 20,000 MLLW NAD27

H04896A 1928 80,000 MLLW NAD27

H09238 1971 10,000 MLLW NAD27

H09239 1971 10,000 MLLW NAD27

H09240 1971 2,500 MLLW NAD27

B00232 1990 50,000 MLLW NAD83

B00236 1990 50,000 MLLW NAD83

B00237 1990 50,000 MLLW NAD83
12 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

B00240 1990 50,000 MLLW NAD83

B00246 1990 50,000 MLLW NAD83

B00247 1990 50,000 MLLW NAD83

B00283 1991 50,000 MLLW NAD83

B00287 1991 50,000 MLLW NAD83

Figure 6. Digital NOS hydrographic survey coverage in the Port Orford region. Some older surveys were not used as they 

have been superseded by more recent surveys. DEM boundary in red
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 13

2) USACE hydrographic channel line surveys

Twenty-two hydrographic channel line surveys were downloaded in xyz format from the USACE 

Portland District website (https://www.nwp.usace.army.mil/op/nwh/xyzcoastal.asp). The data were 

transformed to WGS84 and MHW and changed to shape files using FME and quality checked in ArcMap 

against other bathymetric datasets. 

Table 6: USACE hydrographic surveys used in compiling the Port Orford DEM.

Survey ID Year Original 

Vertical Datum

Original Horizontal 

Datum Resolution

Port Orford 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space from 5 to 30 meters with point 

spacing from 3 to 10 meters

Coos Bay Approaches 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~300 meters with point 

spacing of ~35 meters

Coos Bay Empire 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~22 meters with point 

spacing of ~12 meters

Coos Bay Ranges 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~22 meters with point 

spacing of ~12 meters

Coos Charleston 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space from 10 to 15 meters with point 

spacing of ~8 meters

Coos Entrance Ranges 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space from 15 to 50 meters with point 

spacing from 13 to 18 meters

Coos 

Ferndale Marshfield 2007 MLLW NAD83 Oregon State Plane South (feet)

Line space of ~22 meters with point 

spacing of ~12 meters

Coos Jarvis 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~22 meters with point 

spacing of ~12 meters

Coos North Bend 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~22 meters with point 

spacing of ~12 meters

Coos North Bend Ranges 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~22 meters with point 

spacing of ~12 meters

Coos site E 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~50 meters with point 

spacing of ~25 meters

Coos site F 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~150 meters with point 

spacing of ~25 meters

Coos site H 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~60 meters with point 

spacing of ~22 meters

Coquille Approaches 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~155 meters with point 

spacing of ~40 meters

Coquille Bandon boat 

basin 2007 MLLW NAD83 Oregon State Plane South (feet) Point spacing < 10 meters

Coquille ODMDS 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~60 meters with point 

spacing of ~25 meters

Umpqua River 

Approaches 2007 MLLW NAD83 Oregon State Plane South (feet)

Line space of ~300 meters with point 

spacing of ~25 meters

Umpqua River Entrance 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~15 meters with point 

spacing of ~10 meters

Section 103 Site 2006 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~55 meters with point 

spacing of ~20 meters

Salmon Harbor Reach 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~15 meters with point 

spacing of ~12 meters

Winchester Bay 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space from 8 to 15 meters with point 

spacing of ~10 meters

Barretts Range 2007 MLLW NAD83 Oregon State 

Plane South (feet)

Line space of ~15 meters with point 

spacing of ~12 meters
14 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

Figure 7. Spatial coverage of USACE hydrographic channel line surveys for the Port Orford DEM.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 15

3) Multibeam swath sonar files

Nine multibeam swath sonar surveys were available from the NGDC multibeam database 

(http://www.ngdc.noaa.gov/mgg/bathymetry/multibeam.html) for use in the Port Orford DEM (Fig. 8, 

Table 7). This database is comprised of the original swath sonar files of surveys conducted mostly by the 

U.S. academic fleet. The downloaded data were gridded to 1 arc-second resolution using MB-System. Two 

1994 Ewing surveys by Columbia University, Lamont-Doherty Earth Observatory (LDEO) were not used 

in building the DEM as analysis of the gridded data showed numerous, anomalous spikes and artifacts. 

Most of the multibeam swath surveys offshore southern Oregon were transits rather than dedicated seafloor surveys. All have a horizontal datum of WGS84 geographic and undefined vertical datum, and were 

assumed to be referenced to mean sea level (MSL).

Table 7: Multibeam swath sonar files used in compiling the Port Orford DEM.

Cruise ID Year Original Vertical 

Datum

Original 

Horizontal Datum Institution

AT07L14 2002 assumed Mean Sea 

Level WGS84 geographic Woods Hole Oceanographic Institution (WHOI)

AVON08MV 1999 assumed Mean Sea 

Level WGS84 geographic University of California, Scripps Institution of Oceanography (UC/SIO)

AVON09MV 1999 assumed Mean Sea 

Level WGS84 geographic University of California, Scripps Institution of Oceanography (UC/SIO)

CNTL04RR 2003 assumed Mean Sea 

Level WGS84 geographic University of California, Scripps Institution of Oceanography (UC/SIO)

LWAD99MV 1999 assumed Mean Sea 

Level WGS84 geographic University of California, Scripps Institution of Oceanography (UC/SIO)

Tecfluc 1998 assumed Mean Sea 

Level WGS84 geographic Monterey Bay Aquarium Research Institute (MBARI)

Tran2sou 1998 assumed Mean Sea 

Level WGS84 geographic Monterey Bay Aquarium Research Institute (MBARI)

Figure 8. Spatial coverage of multibeam 

swath sonar files from NGDC multibeam 

database used in the Port Orford region.
16 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

After assessing individual survey quality, the gridded data were transformed to MHW in xyz format 

using FME, displayed in QT Modeler and edited using GEODAS Hydroplot and QT Modeler. Figure 9 

shows a band of anomalous data spikes in survey Tran2sou, which were removed before use in the DEM. 

Difficulties with multibeam data collection included center beam noise errors (Fig. 10) and swath end 

rolling, “smiles and frowns” (Fig. 11). Surveys were manually edited down the center beam and at the 

edges where these errors were most pronounced, before creating a gridded bathymetric surface. Figure 11 

shows the difference between a pre-edited and post-edited bathymetric surface. 

Figure 9. QT Modeler image of anomalous data spikes in the multibeam sonar survey Tran2sou. These spikes 

were removed by clipping out this section of trackline. 

Figure 10. QT Modeler image of multibeam survey LWAD99MV showing center beam noise errors of up to 50 meters. The survey was 

manually edited in strips or individual point to remove the most significant errors. 
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 17

Figure 11. QT Modeler image of cross section comparing gridded bathymetric surfaces of pre-edited data (shown in blue on the graph) and 

the post edited data (shown in red on the graph). 
18 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

4) Oregon Department of Fish and Wildlife/Marine Resources Program Multibeam survey

The Oregon Department of Fish and Wildlife/Marine Resources Program provided two high resolution 

multibeam surveys for Orford Reef south of Cape Blanca (top image in Fig. 12) and for Bandon Reef, the 

near shore area at the entrance to the Coquille River (lower right image in Fig. 12). Information on these 

surveys is detailed in habitat reports (Fox et. al, 1999 and 2000) and was downloaded from the ORDFW 

website (http://www.dfw.state.or.us/MRP/publications/). The surveys were transformed to MHW and 

WGS84 using FME and processed using the GMT ‘blockmedian’ tool, for use in creating a bathymetric 

surface. The full resolution data files were used in the final gridding process.

Figure 12. Images of gridded multibeam surveys provided by Oregon Dept. of 

Fish and Wildlife/MarineReseources Program. Orford Reef in gray box above 

and Bandon Reef in box to lower right.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 19

5) Office of Coast Survey chart soundings

The OCS electronic navigational chart (ENC) sounding data were extracted from chart #18580 and 

converted to MHW; in a region without digital NOS soundings. Soundings were clipped to the multibeam 

sonar surveys, the USACE hydrographic surveys, and the more recent NOS hydrographic surveys. 

Additional soundings digitized from RNCs #18587 and #18588 were added near Coos Bay and Coquille 

River to ensure negative elevations in the bathymetric surface where no other digital sounding data were 

available.

Figure 13. Spatial coverage of the OCS chart sounding data used to compile the Port Orford DEM.

Inconsistencies were identified while merging the bathymetric datasets due to the range in ages of the 

NOS hydrographic surveys and differences in resolution. In areas where more recent data were available, 

the older NOS surveys were either edited or removed. 
20 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

3.1.3 Topography

Three topographic datasets in the Port Orford region were obtained and used to build the Port Orford DEM 

(Table 8; Fig. 14). The USGS NED 1/3 arc-second provided full coverage for the DEM area and the 2002 CSC 

LiDAR dataset covered the entire coastline. NGDC created an additional topographic dataset representing four 

coastal features not fully resolved in the NED or CSC dataset. NGDC evaluated but did not use the Shuttle Radar 

Topography Mission (SRTM) Elevation 1 arc-second DEM available from USGS, as the higher resolution 1/3 arcsecond NED DEMs provided complete coverage.

Table 8: Topographic datasets used in compiling the Port Orford DEM.

Source Year Data Type Spatial

Resolution

Original Horizontal 

Datum/Coordinate 

System

Original 

Vertical 

Datum

URL

USGS 1999-

2006 NED DEM 1/3 arcsecond NAD83 geographic NAVD88(meters) http://ned.usgs.gov/

CSC 2002 LiDAR ~2 meters NAD83 geographic NAVD88

(meters) http://maps.csc.noaa.gov/TCM/

NGDC

digitized 

elevation 

points

~10 meters WGS84 geographic MHW 

(meters)

Figure 14. Spatial coverage of topographic 

datasets used in the Port Orford DEM.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 21

1) USGS NED topographic 1/3 arc-second DEMs

The U.S. Geological Survey (USGS) National Elevation Dataset (NED; http://ned.usgs.gov/) provides

complete 1/3 arc-second coverage of the Port Orford region2. Data are in NAD83 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 2000. The NED DEM included “zero” elevation values over the 

open ocean, which were removed from the dataset by clipping to the combined coastline. The clipping 

process also removed artifacts shown in Figure 15. 

Figure 15. NED topographic data at Coos Bay. Red arrows point to artifacts present in the raw dataset.

 2. The USGS National Elevation Dataset (NED) 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 NAD83, except for AK, which is NAD27. 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 website]
22 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

2) CSC LiDAR topography

The 2002 NASA/USGS Airborne LiDAR Assessment of Coastal Erosion (ALACE) Project

topographic LiDAR dataset was downloaded from the CSC website (http://maps.csc.noaa.gov/TCM/) and 

transformed to WGS84 and MHW using FME.

Figure 16. Spatial coverage of the CSC topographic LiDAR within the Port Orford DEM boundary.

As this dataset was not processed to bare earth and contained elevation values over open water, NGDC 

processed the data to simulate bare earth. First, elevations below 0.85 meters were filtered out, removing 

the majority of water-surface returns. Next, the data were gridded using MB-System to create a 30 meter 

resolution grid that matched the USGS NED topographic dataset. ArcGIS 3D Analyst was used to remove 

points where the difference between the NED and the LiDAR data was greater than 7 meters. Areas where 

data were removed by this technique roughly correspond to false color satellite images representing 

vegetation (Fig. 17; Table 9). It also created a smoother seam between the two datasets.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 23

Table 9: Summary of True Color and Short-Wavelength InfraRed (SWIR) satellite imagery representing surface features 

(https://zulu.ssc.nasa.gov/mrsid/tutorial/Landsat%20Tutorial-V1.html).

Surface Feature True Color SWIR (GeoCover2000)

Red: Band 3 Red: Band 7

Green: Band 2 Green: Band 4

Blue: Band 1 Blue: Band 2

Trees and Bushes olive green shades of green

Crops medium to light green shades of green

Wetland Vegetation dark green to black shades of green

Water shades of blue and green black to dark blue

Urban Areas white to light blue lavender

Bare Soil white to light blue magenta, lavender, or pale pink

Figure 17. Comparison of CSC LiDAR data coverage before and after NGDC processing and NASA Geocover2000 short-wavelength infrared 

image of the Cape Blanca and Port Orford region. A) CSC LiDAR coverage. Green is coverage before processing, red is post processing 

coverage. B) Pink/magenta areas in satellite image have less vegetation than green colored areas.
24 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

3) NGDC digitized elevation points

As neither the NED DEMs nor the CSC LiDAR data fully represent the jetties at Port Orford, Coquille 

River, Coos Bay, and Umpqua River, NGDC created digital representations of the features in ArcMap. 

Elevations assigned to the jetties are based on NGS monument elevations where available or CSC LiDAR 

values (point spacing ~10 meters).

Figure 18. Location and aerial photos of the four NGDC digitized jetties. Photos from USACE photo database 

(https://eportal.usace.army.mil/sites/DVL/default.aspx)

After processing, the topographic data were viewed in ArcMap to make sure that the transitions along dataset 

edges were smooth. The data were then converted to xyz format using FME for the final gridding process.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 25

3.2 Establishing Common Datums

3.2.1 Vertical datum transformations

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

of vertical datums including Mean Lower Low Water (MLLW), Mean Low Water (MLW), and Mean Sea Level 

(MSL). All datasets were transformed to MHW to provide the worst-case scenario for inundation modeling. Units 

were converted from feet to meters as appropriate.

1) Bathymetric data

The NOS hydrographic surveys, the multibeam sonar surveys, the navigation chart soundings, and the 

USACE channel line surveys were transformed from MLLW and MSL to MHW, using constants based on 

the Port Orford tide station (Table 10).

2) Topographic data

The USGS NED 1/3 arc-second DEMs and the CSC topographic LiDAR data were originally 

referenced to NAVD88. Conversion to MHW, using FME software, was accomplished by adding a 

constant offset of -1.853 meters (Table 10) as measured at the Port Orford tide station.

Table 10. Relationship between Mean High Water and other vertical datums at the Port Orford tide station #9431647.

Vertical datum Difference to MHW

MSL -0.805

NAVD88 -1.853

MLW -1.589

MLLW -2.004

3.2.2 Horizontal datum transformations

Datasets used to compile the Port Orford DEM were originally referenced to WGS84 geographic, NAD83 

geographic, NAD27 geographic, or NAD83 Oregon State Plane South datums. The relationships and 

transformational equations between these horizontal datums are well established. All data were converted to a 

horizontal datum of WGS84 geographic using FME software.

3.3 Digital Elevation Model Development

3.3.1 Verifying consistency between datasets

After horizontal and vertical transformations were applied, the resulting ESRI shape files 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 shape files were then converted to xyz files in preparation 

for gridding. Problems included:

• Suspect topographic elevations located on open-ocean in both NED and CSC datasets.

• Inconsistencies between the NED and CSC topographic data. 

• Data errors in multibeam swath sonar surveys, which were expressed as anomalous spikes. Manual editing 

of the multibeam sonar data was necessary to minimize these artifacts. 

• Topographic CSC LiDAR dataset not processed to bare earth. The dataset required filtering of elevation 

values on land and removal of returns from the water surface.

• Digital, measured bathymetric values from NOS surveys date back over 100 years. More recent data, such 

as the USACE hydrographic surveys depths, differed from older NOS data by as much as 10 meters 

nearshore and up to 75 meters in deeper water compared to multibeam data. The older NOS survey data 

were excised where more recent bathymetric data exists.
26 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

3.3.2 Smoothing of bathymetric data

The NOS hydrographic surveys are generally sparse at the resolution of the 1/3 arc-second Port Orford DEM: in 

both deep water and in some areas close to shore, the NOS survey data have point spacing up to 1900 m apart. In 

order to reduce the effect of artifacts in 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-second-spacing ‘pre-surface’ bathymetric grid 

was generated using GMT, an NSF-funded share-ware software application designed to manipulate data for 

mapping purposes (http://gmt.soest.hawaii.edu/).

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

the NGDC multibeam data, the ORDFW multibeam survey data, the ENC sounding data, and the digitized RNC 

sounding data and combined into a single file, along 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 data is sparse or non-existent.

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 Port Orford 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. 19)

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

Figure 19. Histogram of the differences between NOS hydrographic survey H04891 and the 1 arc-second pre-surfaced 

bathymetric grid.

3.3.3 Gridding the data with MB-System

MB-System (http://www.ldeo.columbia.edu/res/pi/MB-System/) was used to create the 1/3 arc-second Port 

Orford DEM. MB-System is an NSF-funded free 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 CSC LiDAR data. Least weight was given to the pre-surfaced 1 arcsecond 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 Port Orford DEM.

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

Dataset Relative Gridding Weight

CSC topographic coastal LiDAR 1,000,000

OR DFW Multibeam surveys 10,000

NGDC Multibeam surveys 1,000

USACE surveys 10,000

Digitized Nautical Charts 100

USGS NED topographic DEM 100

Digitized Jetties 10,000

NOS hydrographic surveys 10

Derived coastline 1

Pre-surfaced bathymetric grid 1
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 27

3.4 Quality Assessment of the DEM

3.4.1. Horizontal accuracy

The horizontal accuracy of topographic and bathymetric features in the Port Orford DEM is dependent upon the 

datasets used to determine corresponding DEM cell values. Topographic features have an estimated accuracy of up

to 10 meters: CSC topographic LiDAR data have an accuracy between 1 and 3 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 sub aerial 

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 manmade 

morphologic change (i.e., channel dredging and building of jetties).

3.4.2 Vertical accuracy

Vertical accuracy of elevation values for the Port Orford DEM is also highly dependent upon the source 

datasets contributing to DEM cell values. Topographic areas have an estimated vertical accuracy between 0.1 to 0.3 

meters for CSC LiDAR 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.
28 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

3.4.3 Slope maps and 3-D perspectives

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

and identification of artificial slopes along boundaries between datasets (e.g., Fig. 20). The DEM was transformed to 

UTM Zone 10 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 UTMtransformed DEM was accomplished using ESRI ArcScene (e.g., Fig. 21). 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 arcsecond Port Orford DEM in its final version.

Figure 20. Slope map of the Port Orford DEM. Flat-lying slopes are white; dark shading denotes 

steep slopes; derived coastline in red.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 29

Figure 21. Perspective view from the southwest of the Port Orford DEM. No vertical 

exaggeration.

3.4.4 Comparison with source data files

To ensure grid accuracy, the Port Orford 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 USACE

hydrographic survey file located at the approach to Coos Bay and the Port Orford DEM is shown in Figure 22. 

Differences range from -4.0 to 3.4, with 39 out of 3829 soundings exceeding 1.0-meter discrepancy from the DEM.

These soundings were located where two USACE surveys overlapped and around the reef at Gregory Point. 

Figure 22. Histogram of the differences between one USACE hydrographic survey and the Port Orford DEM.
30 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

3.4.5 Comparison with NGS geodetic monuments

The elevations of 710 NOAA NGS geodetic monuments were extracted from online shape files of monument 

datasheets (http://www.ngs.noaa.gov/cgi-bin/datasheet.prl), which give monument positions in NAD83 (typically 

sub-mm accuracy) and elevations in NAVD88 (in meters). Monuments installed on lighthouses or buildings were 

not included in assessment of the DEM.

 Elevations were shifted to MHW vertical datum (see Table 10) for comparison with the Port Orford DEM (see 

Fig. 24 for monument locations). Differences between the Port Orford DEM and the NGS geodetic monument 

elevations range from -304 to 60 meters, with the majority of them within ± 2 meters (Fig. 23). Negative values 

indicate that the DEM is less than the monument elevation. Monuments located in a lighthouse, on sand dunes, and 

at a rock quarry had the greatest negative values. The monuments with the greatest positive values were located in 

areas with steep terrain and were scaled from a topographic map and have an accuracy of ± 6 arc-seconds. These 

elevations may not be represented in the NED topographic data or may have been filtered out of the non-bare earth 

CSC LiDAR data during processing

Figure 23. Histogram of the differences between NGS geodetic monument elevations and the Port Orford DEM.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 31

Figure 24. Location of NGS geodetic monuments, shown as green triangles, and the NOAA Port Orford tide station, red 

circle. NGS monument elevations were used to evaluate the DEM.
32 DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON

4. SUMMARY AND CONCLUSIONS

An integrated bathymetric–topographic digital elevation model of the Port Orford, Oregon region, with cell 

spacing of 1/3 arc-second, was developed for the Pacific Marine Environmental Laboratory (PMEL) NOAA Center 

for Tsunami Research. The best available digital data from U.S. federal, state and local agencies 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 ESRI ArcGIS, FME, GMT, MB-System and Quick Terrain 

Modeler software. 

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

• Conduct hydrographic surveys for near-shore areas, especially in bays and river inlets.

• Complete bathymetric–topographic LiDAR surveying of entire region, especially within coastal zones.

• Process CSC topographic LiDAR data to bare earth.

• Re-survey older, low resolution NOS hydrographic surveys in deeper waters.

5. ACKNOWLEDGMENTS

The creation of the Port Orford DEM was funded by the NOAA Pacific Marine Environmental Laboratory. The 

authors thank Chris Chamberlin and Vasily Titov (PMEL); Daniel Proudfit of U.S. Army Corp of Engineers, 

Portland District; and Arlene Merems and David Fox of Oregon Department of Fish and Wildlife/Marine Resources 

Program.

6. REFERENCES

Nautical Chart #18580 (RNC and ENC), 22nd Edition, 2005. Cape Blanco to Yaquina Head. Scale 1: 191,730. U.S. 

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

Nautical Chart #18587 (RNC), 70th Edition, 2005. Coos Bay. Scale 1:20,000. U.S. Department of Commerce, 

NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18588 (RNC), 37th Edition, 2003. Coquille River Entrance. Scale 1:20,000. U.S. Department of 

Commerce, NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18589 (RNC), 16th Edition, 2007. Port Orford to Cape Blanco. Scale 1:40,000. U.S. Department of 

Commerce, NOAA, National Ocean Service, Coast Survey.

Nautical Chart #18600 (RNC and ENC), 14th Edition, 2002. Trinidad Head to Cape Blanco. Scale 1:196,948. U.S. 

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

Nautical Chart #18601 (RNC), 14th Edition, 2007.Cape Sebastian to Humbug Mountain. Scale 1:40,000. U.S. 

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

Fox, D.S.; Amend, M.; Merems, A. 1999. 1999 Nearshore Rocky Reef Assessment, Final Report for 1999 Grant 

Contract No.99-072. Oregon Department of Fish and Wildlife/Marine Program.

Fox, D.S.; Amend, M.; Merems, A.; Appy, M. 2000. 2000 Nearshore rocky reef assessment. Newport, OR: Oregon 

Department of Fish and Wildlife. 32 pp.
DIGITAL ELEVATION MODEL FOR PORT ORFORD, OREGON 33

7. DATA PROCESSING SOFTWARE

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

FME 2007 GB – Feature Manipulation Engine, developed and licensed by Safe Software, Vancouver, BC, Canada, 

http://www.safe.com/

GEODAS v. 5 – Geophysical Data System, free software 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, free software 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, free software 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 (APL) and maintained and licensed by Applied Imagery, http://www.appliedimagery.com/