Decision Support for Coastal Science and Management

Lidar Vegetation Mapping in National Parks:

Gulf Coast Network

Airborne lidar (Light Detection and Ranging) is an active remote sensing technique used to collect accurate elevation 

data over large areas. Lidar provides an extremely high level of regional topographic detail, which makes this technology an 

essential component of U.S. Geological Survey (USGS) science strategy. The USGS Coastal and Marine Geology Program 

(CMGP) has collaborated with the National Aeronautics and Space Administration (NASA) and the National Park Service 

(NPS) to acquire dense topographic lidar data in a variety of coastal environments.

EAARL Technology

The Experimental Advanced 

Airborne Research Lidar (EAARL) is 

an airborne lidar system that provides 

unique capabilities to survey coral 

reefs, nearshore benthic habitats, coastal 

vegetation, and sandy beaches (Wright 

and Brock, 2002). Operating in the bluegreen portion of the electromagnetic 

spectrum, the EAARL is specifically 

designed to measure submerged 

topography and adjacent coastal land 

elevation in a single scan of transmitted 

laser pulses (Nayegandhi and others, 

2009). 

Effective coastal management plans 

need accurate and detailed representation 

of the horizontal and vertical structure of 

plant communities, also called canopy 

structure. EAARL is a full-waveform 

digitizing lidar. It records backscattered 

laser energy above a very low time 

interval, creating a data record that is 

highly sensitive to minor changes in 

vegetation structure. These “smallfootprint” EAARL waveforms can be 

used to generate accurate estimates of the 

spatial arrangement in coastal vegetation 

communities.

To describe the vertical structure of 

a vegetation canopy, several individual 

small-footprint laser pulses are combined 

to create a composite “large-footprint” 

waveform that defines a larger horizontal 

area (fig. 1). This process is called 

composite waveform analysis. The 

size of this composite footprint can be 

determined in post-flight processing 

software, unlike large-footprint lidar 

systems, whose footprint size is 

constrained by hardware prior to data 

acquisition. The size of the composite 

footprint depends on the density of the 

lidar data, the nature of the forested 

terrain, and the desired horizontal 

resolution of the end product.

Coastal Applications

The National Park Service (NPS) 

has been mandated to improve park 

management through greater reliance 

on scientific knowledge, and it achieves 

this goal through its Inventory and 

Monitoring (I&M) Program. EAARL 

lidar data were acquired by the USGS 

in collaboration with the NPS I&M 

Program to document and interpret 

vegetated habitats along coastal areas in 

the NPS Gulf Coast Network (GULN). 

This network extends from the western 

third of Florida through Mississippi and 

Louisiana to the southeastern quarter 

of Texas and extends northward to 

Nashville, Tennessee.

EAARL-derived vegetation 

measurements are being used to 

provide reliable and consistent 

quantitative information on the structural 

Figure 1. EAARL lidar waveforms can be 

combined to create a composite waveform.

A

Louisiana

Jean Lafitte National Historical 

Park and Preserve

Fact Sheet 2011–3137

November 2011

B

C

Figure 2. Map showing the study area (A), 

which is approximately two thirds marsh (B). 

The remaining area is swamp forest (C).

U.S. Department of the Interior

U.S. Geological Survey
characteristics of park vegetation 

resources at both small and large 

scales. One recent study evaluates the 

capabilities of EAARL technology 

in predicting the presence or absence 

of coastal vegetation communities 

in Barataria Preserve at Jean Lafitte 

National Historical Park and Preserve, 

Louisiana (JELA) (fig. 2; PalaseanuLovejoy and others, 2009). Bare-earth 

elevation, canopy height, canopy 

reflection ratio, and the height of median 

energy are examples of metrics that can 

be derived from EAARL compositefootprint waveforms (fig. 3). In coastal 

communities, bare-earth elevations can be 

used to model the hydrology of areas and 

therefore be helpful in predicting water 

availability to plant communities. Canopy 

height is a long-established indicator 

of site quality in forestry applications. 

Canopy reflection ratio is a relative 

measure of canopy cover, and height of 

median energy has been found to be a 

good predictor of biomass and structural 

attributes in tropical forests. Applied in 

a similar manner to coastal vegetation 

communities, height of median energy 

could be used to help identify structural 

changes across environmental gradients 

and perhaps assess damage to forests 

from storms and parasite infestations. 

Maps generated from lidar-based 

vegetation measurements are used 

extensively for conservation, land 

management applications, and decision 

support systems. These maps can also be 

used in change analysis and assessment 

of extreme storm impact on different 

vegetation communities. 

In addition to the research efforts 

taking place in the GULN, the USGS also 

collaborates with two other NPS I&M 

Program Networks, the South Florida 

Caribbean Network and the Northeast 

Coastal and Barrier Network. Lidar 

data have been collected using EAARL 

technology in all three NPS networks 

to document and interpret marine 

benthic communities, barrier island 

geomorphology, and vegetated habitats in 

coastal areas.

References Cited

Nayegandhi, Amar, Wright, C.W., and 

Brock, J.C., 2009, EAARL—An airborne lidar system for mapping coastal 

and riverine environments, in Bayer, 

J.M., and Schei, J.L., eds., PNAMP 

Bare Earth

NAVD 88 (m)

2 m

0 m

Canopy

Reflection

Ratio

1.0

0.0

Canopy Height

30 m

0 m

Height of

Median

Energy

30 m

0 m

0 2 4 8 Miles

0 2 4 8 Kilometers

 N 

↑

Figure 3. Examples of EAARL measurements from Jean Lafitte National Historical Park and 

Preserve, Louisiana. Abbreviation: m, meter.

Special Publication—Remote sensing applications for aquatic resource 

monitoring: Pacific Northwest Aquatic 

Monitoring Partnership, Cook, Washington, p. 3–5.

Palaseanu-Lovejoy, Monica, Nayegandhi, 

Amar, Brock, J.C., Woodman, Robert, 

and Wright, C.W., 2009, Evaluation of 

airborne lidar data to predict vegetation 

presence/absence: Journal of Coastal 

Research, Special Issue 53, p. 83–97.

Wright, W.C., and Brock, J.C., 2002, 

EAARL: A lidar for mapping shallow 

coral reefs and other coastal environments, in Proceedings of the Seventh 

International Conference on Remote 

Sensing for Marine and Coastal 

Environments Miami, Fla., 20–22 May 

2002, Veridian, Ann Arbor, Mich., 1 

CD-ROM.

Contact Information

John C. Brock

Coastal and Marine Geology Program

USGS National Center, Mail Stop 915–B

12201 Sunrise Valley Drive

Reston, VA 20192

jbrock@usgs.gov

Monica Palaseau-Lovejoy

U.S. Geological Survey

St. Petersburg Coastal and Marine

Science Center

600 4th Street South

St. Petersburg, FL 33701

mpal@usgs.gov

Martha Segura

Gulf Coast Network

National Park Service

Lafayette, LA 70506

Martha_Segura@nps.gov

http://ngom.usgs.gov/dsp