About the Land Cover Analysis Tool (LCAT)
In 2006, the Eastern Geographic Science Center began a joint project
to develop a custom application to provide enhanced public access to
USGS’s National Land Cover Database (NLCD). The resulting Land Cover
Analysis Tool (LCAT) allows users to quickly locate, display, and
download data from the National Land Cover Dataset (NLCD) , including
the recently developed NLCD Change Product, which displays changes in
land cover between 1992 and 2001.
What Makes LCAT Different?
- Includes new 1992-2001 Change Product
- Facilitates Visual Analysis (base map layers are visible beneath
the Land Cover)
- Performs Statistical Analysis
- Download Shapefile of user-defined Area-of-Interest (can be an
irregular polygon)
LCAT allows users to clip, display, and download NLCD data using a
variety of polygons, including city, county and watershed boundaries,
uploaded shapefiles, as well as polygons defined 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.
LCAT is
currently being Beta tested, both within USGS and by a group
of external volunteers.
Anyone wishing to become a beta-tester or
having other questions about LCAT should submit an automated request
at: http://diseasemaps.usgs.gov/landcover
Layers
This panel allows the choice of land cover
layers to display on the map. If a layer is greyed-out it means it is
not visible at the current scale. Layers can be turned on/off a layer
using the checkbox.
The USGS land cover data are made up
of small coloured cells, each a square roughly 30 meters on a side.
Each cell is classified as a category (class) of land cover, or in the
case of the Land Cover Change Product cells where change has occurred,
the cells are colored yellow. 1992 and 2001 landcover are classified at
the Anderson II level (21-36 classes, respectively). The 1992-2001
Change Product is classified at the Anderson I level (8 classes. Also
included are two derivative products from the 2001 landcover dataset,
impervious surface and forest canopy.
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Transparency Slider
If a land cover layer is
displayed, you can adjust its transparency such that base Landsat
imagery can be viewed beneath the land cover layer
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Region of Interest (ROI)
This tool allows a discrete
area of land cover data to be selected by the user, its summary
statistics displayed, and the data downloaded to the user’s desktop.
ROI’s can be chosen from a menu of political and watershed boundaries,
from a shapefile uploaded by the user, or delineated by the user on the
screen using the digitize function.
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Filtering
If a land cover layer is turned on then
this pane will display the possible cell colors, corresponding land
cover class designations, and their meanings. Areas of change in the
1992-2001 Change Product are also labeled with two digit “from-to”
codes. The filtering tool allows the user to turn on or off individual
classes or groups of classes. Click on the Apply button to make the
selected changes visible on the map.
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Statistics
This panel allows the user to calculate
the areal extent and relative percentage of land cover class values for
a user-selected ROI. If an ROI is not defined, the area visible on the
screen will be analyzed by default.
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U.S. Department of the
Interior | U.S. Geological Survey
