DA
United States
Environmental Protection
Agency
EPA/600/R-04/083
ATtlLA
Analytical Tools Interface
for Landscape Assessments
Office of Research and
Development
National Exposure
Research Laboratory
Environmental Sciences
Division
Landscape Ecology
Branch
Environmental management practices are trending away from sim-
ple, local-scale assessments toward complex, multiple-stressor
regional assessments. Landscape ecology provides the theory
behind these assessments while geographic information systems
(GIS) supply the tools to implement them. A common application
of GIS is the generation of landscape metrics, which are quantita-
tive measurements of the environmental condition or vulnerability
of an area (e.g., ecological region or watershed). The generation of
these metrics can be a complex, lengthy undertaking, requiring
substantial GIS
expertise.
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The U.S. EPA
Landscape
Ecology Branch
has developed a
user-friendly
interface to facili-
tate this process.
The Analytical
Tools Interface
for Landscape
Assessments
(ATtlLA) is an
easy to use
Arc View exten-
sion that calcu-
lates many com-
monly used land-
scape metrics. By
providing an intuitive interface, the extension provides the ability
to generate landscape metrics to a wide audience, regardless of
their GIS knowledge level. ATtlLA is a robust, flexible program.
It accepts data from a broad range of sources and is equally suit-
able across all landscapes, from deserts to rain forests to urban
areas.
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Four families of metrics are included in the extension: landscape
characteristics, riparian characteristics, human stressors, and physi-
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ATtlLA
Analytical Tools Interface for Landscape Assessments
1973
cal characteristics. Each group has a dialog
to accept user input on which metrics to cal
culate and what input data
to use. Landscape charac-
teristics are related to land
cover proportions and
patch metrics (e.g. percent
grassland cover or number ai
size of grassland patches).
Riparian characteristics descr
land cover adjacent to and ne
streams (e.g. percent of crop
within 30 meters of streams).
Human Stressors are concern
population, roads, and land i
practices (e.g. population cha
or extent of human use), and
physical characteristics provi
statistical summaries of such
attributes as elevation and
slope.
Once metrics have been calct
the extension has three types
output display available. Th<
displays areas ranked by ind
metric values, the second ran
by a weighted index made uj
or more metrics, and the thin
a bar chart of selected areas and metrics.
Because of the size of landscape data sets
and the complexity of the calculations to gen-
erate some metrics, we recommend a mini-
mum of a Pentium II266 MHz (or equiva-
lent) with 32 MB of memory. A preferred
system would include a Pentium II 400MHz
(or better) with 64 MB of memory and a fast
(<8 ms) hard drive or better.
To use the ATtlLA, you will need version 3.1
or later of Arc View and the Spatial Analyst
version 1.1 extension. Both UNIX and
Windows (95, 98, ME, XP, and NT) environ-
ments are supported.
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For further information contact:
Donald W. Ebert
U.S. Environmental Protection Agency
National Exposure Research Laboratory
Environmental Sciences Division
Landscape Ecology Branch
P.O. Box 93478
Las Vegas, NV 89193-3478
Phone: (702) 798-2158
E-mail: ebert.donald@epa.gov
WEBSITE ANNOUNCEMENT
OCTOBER 2001
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