Coastal National Elevation Database

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2018–3037

June 2018

Introduction

The Coastal National Elevation Database (CoNED) Applications Project develops 

enhanced topographic (land elevation) and bathymetric (water depth) datasets that serve as 

valuable resources for coastal hazards research (Danielson and others, 2016; Thatcher and 

others, 2016). These datasets are used widely for mapping inundation zones from riverine 

flood events, hurricanes, and sea-level rise and for other Earth science applications, such as 

sediment transport, erosion, and storm impact models.

CoNED is a U.S. Geological Survey (USGS) Coastal-Marine Hazards and Resources 

Program (formerly Coastal and Marine Geology Program) activity centered at the USGS 

Earth Resources Observation and Science Center and distributed at other USGS Science 

Centers. As part of the vision for a 3D Nation, the CoNED Project is working collaboratively with the USGS National Geospatial Program, the National Oceanic and Atmospheric 

Administration, and the U.S. Army Corps of Engineers through the Interagency Working 

Group on Ocean and Coastal Mapping to build integrated elevation models in the coastal 

zone by assimilating the land surface topography with littoral zone and continental shelf 

bathymetry. Several nongovernmental organizations and Federal agencies, including the 

Department of the Interior Pacific Islands Climate Adaptation Science Center, the National 

Park Service, the Nature Conservancy, the Louisiana Coastal Protection and Restoration 

Authority, and numerous academic institutions, partner to make CoNED a success.

Goals and Benefits

The primary goal of CoNED is to provide seamless, cross-shore integrated topobathymetric digital elevation models (TBDEMs) to support coastal and marine spatial planning. 

CoNED also enhances the USGS 3D Elevation Program (3DEP) by providing coastal communities with integrated elevation information for coastal zone decision support applications on the U.S. ocean coasts and the Great Lakes.

CoNED fulfills a fundamental need of the USGS Land Resources (formerly Climate 

and Land Use Change) Science Strategy and responds directly to USGS science goals by

• Improving the understanding and prediction of coastal response to sea-level rise, climate 

change, and human development;

• Developing TBDEMs at select focus regions for scientific investigations and applications for land change science research to support coastal and marine spatial planning; 

and

• Providing seamless TBDEMs extending from onshore coastal areas through the U.S. 

Exclusive Economic Zone out to a 3-nautical mile limit offshsore.

The CoNED methodology improves and implements technology and techniques for 

the integration of coastal topobathymetric mapping data, such as with land water masking 

algorithms and complex geospatial multitemporal frameworks (Danielson and others, 

2016).

CoNED TBDEMs

CoNED TBDEM development is focused in select regions around the U.S. coast, 

such as the Northern Gulf of Mexico, the eastern seaboard from New England to North 

Carolina, California, the Pacific Northwest, the North Slope of Alaska, and select western 

Pacific islands and atolls. CoNED TBDEMs are constructed from multisource topographic 

and bathymetric data that are aligned vertically and horizontally to a common reference 

system.

The first high-resolution CoNED TBDEM was produced in 2012 for Mobile Bay, 

Alabama, the fourth largest estuary in the United States (Gesch, 2013). Highly detailed 

TBDEMs continue to be developed for coastal regions including Chesapeake Bay, 

Delaware, New England, New Jersey, the Northern Gulf of Mexico, Central California, 

Southern California, Puget Sound, and Majuro Atoll, Republic of the Marshall Islands.

CoNED Topobathymetric Digital Elevation Data Support Critical Applications

Land

elevation

Water 

depth

Sea-level

rise

Image from Maria Kottermair, 

University of Guam, 2016

Flooding

Sea-cliff

erosion

Disaster/

inundation

Hurricanes

NASA, 2017

Landscape

change and 

vulnerability
CoNED Scientific Research

The onshore-offshore cross ecosystem 

coverage of CoNED TBDEMs supports scientific research assessing the effects of various 

changes to vulnerable coastal regions subject 

to powerful storms, including hurricanes on 

the east and gulf coasts and extratropical 

cyclones on the west coast.

In support of hazard vulnerability and 

ecosystem resilience research, complex 

configurations of coastal emergent wetlands 

and open water were delineated by CoNED 

scientists to provide wetland extent information that is valuable for storm surge and 

sediment transport models, shoreline change 

detection analysis, and wetland classification 

maps. The accuracy of coastal land elevation 

maps directly affects the reliability and usefulness of elevation based sea-level rise vulnerability and inundation assessments (Gesch, 

2013). Therefore, detailed and comprehensive 

CoNED TBDEMs are a key variable in understanding the likely effects of natural hazards.

Sea cliff and bluff erosion is a serious 

hazard for coastal infrastructure and residential dwellings. The availability of CoNED 

TBDEMs and high-resolution 3D point clouds 

from light detection and ranging (lidar) has 

led to advancements in quantifying volumetric 

change in areas vulnerable to sea cliff and 

bluff failure (Palaseanu-Lovejoy and others, 

2016). Coastal change monitoring through 

automatically extracted cliff and bluff metric 

profiles has important benefits to local communities for analyzing economic resource 

planning and hazard mitigation.

The lack of Pacific Islands TBDEMs led 

CoNED researchers to use advanced remote 

sensing technologies to develop land surface 

topography from Structure-from-Motion point 

clouds derived from unmanned aerial system 

photography and satellite-derived bathymetry 

from Landsat and WorldView imagery (Poppenga and others, 2018). Lidar data, acquired 

along the north coast of Alaska from 2009 

to 2012, were used to produce detailed land 

elevations to establish a modern shoreline 

position for shoreline change and coastal 

hazards assessments and evaluating landscape 

patterns.

References

Danielson, J.J., Poppenga, S.K., Brock, J.C., 

Evans, G.A., Tyler, D.J., Gesch, D.B., 

Thatcher, C.A., and Barras, J.A., 2016, 

Topobathymetric elevation model development using a new methodology—Coastal 

National Elevation Database: Journal of 

Coastal Research, no. SI 76, p. 74–88. 

[Also available at https://doi.org/10.2112/

SI76-008.]

Gesch, D.B., 2013, Consideration of vertical 

uncertainty in elevation-based sea-level rise 

assessments—Mobile Bay, Alabama case 

study: Journal of Coastal Research, no. SI 

63, p. 197–210. [Also available at https://

doi.org/10.2112/SI63-016.1.]

National Aeronautical and Space Administration [NASA], 2017, Irma (Atlantic Ocean): 

NASA web page, accessed October 2017 

at https://www.nasa.gov/feature/goddard/2017/irma-atlantic-ocean.

Palaseanu-Lovejoy, M., Danielson, J., 

Thatcher, C., Foxgrover, A., Barnard, P., 

Brock, J., and Young, A., 2016, Automatic 

delineation of seacliff limits using lidarderived high-resolution DEMs in southern 

California: Journal of Coastal Research, 

no. SI 76, p. 162–173. [Also available at 

https://doi.org/10.2112/SI76-014.]

Poppenga, S.K., Palaseanu-Lovejoy, M., 

Gesch, D.B., Danielson, J.J., and Tyler, 

D.J., 2018, Evaluating the potential for

near-shore bathymetry on the Majuro Atoll,

Republic of the Marshall Islands, using

Landsat 8 and WorldView-3 imagery: U.S.

Geological Survey Scientific Investigations

Report 2018–5024, 22 p. [Also available at

https://doi.org/10.3133/sir20185024.]

Thatcher, C.A., Brock, J.C., Danielson, J.J., 

Poppenga, S.K., Gesch, D.B., PalaseanuLovejoy, M.E., Barras, J.A., Evans, G.A., 

and Gibbs, A.E., 2016, Creating a Coastal 

National Elevation Database (CoNED) 

for science and conservation applications: 

Journal of Coastal Research, no. SI 76, 

p. 64–73. [Also available at https://doi.

org/10.2112/SI76-007.]

For More Information

CoNED information can be found at 

https://topotools.cr.usgs.gov/coned/ or by 

contacting Jeffrey J. Danielson at 

daniels@usgs.gov. 

Majuro Atoll, Republic of the Marshall 

Islands, TBDEM

Northern Gulf of Mexico, including 

Mobile Bay, Alabama, TBDEM

Monterey Bay, central California, 

TBDEM

San Francisco Bay area, California, 

TBDEM

Photographs and images from the 

U.S. Geological Survey, unless otherwise 

credited. 

Publishing support provided by the Rolla 

Publishing Service Center.

ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

https://doi.org/10.3133/fs20183037