Web-Based Geospatial Tools to Address Hazard Mitigation, 

Natural Resource Management, and Other Societal Issues

a suite of Web-based geospatial applications 

that will incorporate USGS and cooperating 

partner data into the decision making process 

for a variety of critical issues. Examples of 

Web-based geospatial tools being used to 

address societal issues follow.

Mapping, Monitoring, and Analysis 

of Environmental Mercury

Mercury in our environment—air, 

water, soil, and especially our food—poses 

significant hazards to human health, particularly for developing fetuses and young 

children. Because of the importance of this 

issue and the length of time it has been studied, large and complex data sets of mercury 

concentrations in various media and associated ancillary data have been generated by 

many Federal, State, Tribal, and local agencies. To facilitate the efficient and effective 

use of these data in managing and mitigating 

human and wildlife exposure to mercury, 

the U.S. Geological Survey and the National 

Federal, State, and local government 

agencies in the United States face a broad 

range of issues on a daily basis. Among these 

are natural hazard mitigation, homeland 

security, emergency response, economic and 

community development, water supply, and 

health and safety services. The U.S. Geological Survey (USGS) helps decision makers 

address these issues by providing natural 

hazard assessments, information on energy, 

mineral, water and biological resources, 

maps, and other geospatial information.

Increasingly, decision makers at all 

levels are challenged not by the lack of 

information, but by the absence of effective 

tools to synthesize the large volume of data 

available, and to utilize the data to frame 

policy options in a straightforward and 

understandable manner. While geographic 

information system (GIS) technology has 

been widely applied to this end, systems 

with the necessary analytical power have 

been usable only by trained operators. The 

USGS is addressing the need for more accessible, manageable data tools by developing 

Institute of Environmental Health Sciences 

have developed a Web site for visualizing 

and studying the distribution of mercury. 

The Environmental Mercury Mapping, 

Modeling, and Analysis (EMMMA) Web 

site is designed to support environmental 

and health researchers, as well as land and 

resource managers, by providing useful data, 

map products, and Web-based tools (Hearn 

and others, 2006; http://emmma.usgs.gov). 

Components of EMMMA include:

•	 Online mapping tools, maps, imagery, and 

other thematic data used to display and 

analyze mercury data and to print maps 

(fig. 1). USGS mapping data provide a 

nationwide geographic reference composed of aerial photographs, satellite imagery, and geospatial data for land cover, 

elevation, hydrology, transportation, and 

geographic names. These data provide a 

useful geographic context for the mercury 

data displayed on top of them.

•	 An online model to describe mercury 

in fish tissue, which standardizes the 

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2009–3022

June 2009

Figure 1. EMMMA’s Data Mapper allows users to navigate to and download data from selected locations, and also overlay these data on top 

of topographic maps, satellite imagery, and aerial photographs.
concentration of mercury in fish to enable 

normalized comparisons among different 

species, individuals of different lengths, 

and samples of different types. The 

National Descriptive Model for Mercury 

in Fish Tissue (NDMMFT) is applied to 

a comprehensive national compilation 

of fish-tissue data to detect spatial and 

temporal trends in mercury concentrations 

that would otherwise be obscured (Wente, 

2004). Modeled data from EMMMA can 

aid researchers in spotting significant 

trends in the environment, and also can be 

used by State agencies to develop more 

comprehensive and cost-effective fish 

consumption advisories (fig. 2).

The Land Cover Analysis Tool

USGS’s National Land Cover Dataset 

(NLCD) is used widely by scientists and 

land managers to assess changes in land 

cover that affect water quality, wildlife 

habitat, human and animal population 

distribution, carbon storage related to 

global climate change, and other important 

environmental, ecological, and societal 

examples. The Land Cover Analysis Tool 

(LCAT) is a Web-based tool kit that allows 

users to quickly locate, display, and download NLCD data, including the recently 

developed NLCD Change Product, which 

displays changes in land cover between 

1992 and 2001 (http://lcat.usgs.gov).

LCAT allows users to clip, display, 

and download NLCD data using a variety 

Figure 2. This graph shows a mercury versus fish-length curve fitted by the NDMMFT using 

mercury data for smallmouth bass (dark blue curve) from a U.S. lake. Using this curve the 

model can generate curves for other locally occurring species of fish (walleye, northern pike, 

and carp are shown here) and predict expected mercury content for a given length.

of polygons, including State, county, city, 

and watershed boundaries; and uploaded 

GIS shapefiles, including polygons defined 

onscreen by the user. Additional features 

include the ability to display individual land 

cover classes on top of user-selected maps or 

imagery and the ability to generate and print 

reports detailing the land cover composition 

within selected areas. User-selected change 

pairs (for example, forest to urban) can also 

be displayed on top of satellite imagery to 

provide context for areas of change. An 

example of the type of analysis provided by 

LCAT is shown in figure 3.

Figure 3. LCAT enables users to rapidly calculate and download various land cover data 

statistics for a variety of user-defined areas. This figure shows A, the results of calculating 

the 2001 NLCD for Montgomery County, Md.; and B, a graphical representation in the form 

of a pie diagram and the data table. LCAT requires no special knowledge or software; this 

calculation was completed in less than 5 seconds.

NLCD_FULL_2001

Montgomery [COUNTIES]

Total Area Analyzed: 131104.5h

Colour Value % Area (h) Description

81 29.4 38771.2 Pasture/Hay

41 25.7 33864.5 Deciduous Forest

21 12.6 16638.0 Open Space

82 10.9 14310.8 Cultivated Crops

22 10.0 13248.8 Low Intensity

23 3.8 4952.4 Medium Intensity

42 2.3 3026.2 Evergreen Forest

11 1.9 2452.3 Open Water

24 1.2 1551.1 High Intensity

90 1.1 1454.4 Woody Wetlands

31 0.8 1055.2 Barren Land (Rock/Sand/Clay)

95 0.4 515.3 Emergent Herbaceous Wetlands

43 0.0 12.0 Mixed Forest
Figure 4. The Ecosystem Portfolio Model allows users to quickly develop suitability maps drawn from elected ecological and other physical 

data. The red bordered rectangle above shows the extent of an area between the Everglades and Biscayne National Parks that was analyzed for 

relative suitability. Biodiversity, ecosystem restoration potential, and low landscape fragmentation metrics were chosen as priorities.

The South Florida Ecosystem agricultural areas. This project will con- communities in understanding and reducPortfolio Model tribute to improved public understanding ing their natural-hazards vulnerability 

and awareness of the complex ecological, (http://geography.wr.usgs.gov/science/ Intense pressures for development of environmental, and socioeconomic issues lupm.html). the land outside of the Urban Development involved in land use decisions in southeast The LUPM builds upon financial- Boundary in Miami-Dade County, Florida, Florida, and also offers a useful approach portfolio theory, a method for evaluating threaten to impact both the Everglades and for other areas in the United States where alternative investment choices based on Biscayne National Parks. In response, the there are competing visions for land use.

U.S. Geological Survey, in cooperation with the estimated distribution of risk and return 

the National Park Service and the Whar- from different investment options. The Application of the Land Use ton School of Economics, has developed LUPM been has developed into an interaca prototype for a Web-enabled geospatial Portfolio Model to Seismic Hazard tive, GIS-based decision support system 

information tool—the South Florida Eco- Mitigation in Memphis, Tennessee that stakeholders can use to select locasystem Portfolio Model, or EPM. The EPM tions in which to invest a hazard mitiga- The City of Memphis and surround- allows users to evaluate hypothetical future tion budget, evaluate metrics such as the ing Shelby County lie within the New land use and land cover patterns in terms of Madrid Seismic Zone, which extends mean and variance of community wealth, habitat availability, indicators of ecological health, water quality criteria, land price from northeast Arkansas through south- and compare and rank policies. The model 

changes, and quality of life indicators. The east Missouri and western Tennessee, and is unique in that it allows users to think 

criteria and indicators are chosen to be western Kentucky to southern Illinois. through various levels of risk tolerance and 

sensitive to land use and land cover relevant Historically, Shelby County has been the hazard acceptability and to compare the 

to decision makers and stakeholders, and site of some of the largest earthquakes in cost effectiveness of alternative policies.

indicative of future trends. Users may North America. Earthquakes with esti- Initial results from LUPM runs demassign weights to these criteria to reflect mated magnitudes between 7.5 and 8.0 onstrate the effect of earthquake probability 

their views regarding their relative impor- occurred in this area between 1811 and estimates, planning horizons, and the cost tance. An example of ecological criteria is 1812 (Gomberg and Schweig, 2003). The of mitigation estimates on hazard mitigation shown in figure 4, along with the evaluation City of Memphis and portions of Shelby investments (Bernknopf and others, 2007). results. The EPM project uses contributions County have been mapped by the USGS to Also, the desktop version of LUPM is being from conservation ecology, landscape ecol- assess the level of seismic hazard (fig. 5; 

ogy, decision science, real estate econom- modified to create a Web-based version, http://earthquake.usgs.gov/regional/

ics, ecological economics, urban planning, ceus/index.php which will provide managers and policy ). Shelby County was 

GIS analysis, and Web technologies. In the chosen as an area to evaluate the Land makers with a simplified interface to better 

next phase, the Web-based EPM will be Use Portfolio Model (LUPM), a model- understand how the model works and how 

extended to other areas of South Florida ing, mapping, and risk communication it can benefit the analysis of hazard mitigafacing development pressure in natural and tool that can assist public agencies and tion policies.
Figure 5. One application of the LUPM in Memphis is to provide a planning tool for municipal authorities responsible for schools, police 

stations, fire stations, and other public buildings. The LUPM will allow managers to test various scenarios for the mitigation of seismic risk to 

these assets and evaluate mitigation costs required to lower the risk from specified seismic events.

References Cited

Bernknopf, R.L., Hearn, P.P., Wein, 

A.M., and Strong, David, 2007, The 

effect of scientific and socioeconomic 

uncertainty on a natural hazards 

policy choice, in International Congress on Modeling and Simulation—

MODSIM07, December 2007, Christchurch, New Zealand: Christchurch, 

Modeling and Simulation Society of 

Australia and New Zealand Proceedings, p. 1702–1708.

Gomberg, J., and Schweig, E., 2003, 

Earthquake hazard in the heart of the 

homeland: U.S. Geological Survey 

Fact Sheet 131–02, 4 p. (Also available 

at http://pubs.usgs.gov/fs/fs-131-02/.)

Hearn, P.P., Wente, S.P., Donato, 

D.I., and Aguinaldo, J.J., 2006, 

EMMMA—A Web-based system 

for environmental mercury mapping, modeling, and analysis: U.S. 

Geological Survey Open-File Report 

2006–1086, 13 p. (Also available 

at http://erg.usgs.gov/isb/pubs/

ofrs/2006-1086/ofr2006-1086.pdf.)

Wente, S.P., 2004, A statistical model and 

national data set for partitioning fishtissue mercury concentration variation 

between spatiotemporal and sample 

characteristic effects: U.S. Geological 

Survey Scientific Investigations Report 

2004–5199, 15 p. (Also available at 

http://pubs.usgs.gov/sir/2004/5199/

pdf/2004-5199.pdf.) 

 Author–Paul P. Hearn, Jr.

For more information, please contact

EMMMA, LCAT, and the Memphis LUPM

Paul P. Hearn, Jr.

U.S. Geological Survey

Eastern Geographic Science Center

MS 521, National Center

12201 Sunrise Valley Drive

Reston, VA 20192

Phone: (703) 648–6287

E-mail: phearn@usgs.gov

South Florida EPM

Bill Labiosa

U.S. Geological Survey

Western Geographic Science Center

MS 531, 345 Middlefield Road

Menlo Park, CA 94025

Phone: (650) 329–4279

E-mail: blabiosa@usgs.gov