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Methodology and Interpretation
FAVGSIZE - Average forest patch size
Average forest patch size is calculated by dividing total forest area by the
number of forest patches in the 3 km grid cell reporting unit. Values are reported
in meters2. A patch is defined as adjacent forest pixels, including
diagonals. An irregularly shaped patch may be split into several patches by the
grid cell boundary, inaccurately decreasing the metric value. A grid cell with many
small patches is representative of a highly fragmented landscape. Fragmented forests
provide habitat for edge species, but are poor for interior species, and are
unlikely to provide migration corridors.
Quantile: Each class contains an approximately equal number (count) of features. A quantile
classification is well-suited to linearly distributed data. Because features are grouped by the number
within each class, the resulting map can be misleading, in that similar features can be separated into
adjacent classes, or features with widely different values can be lumped into the same class. This
distortion can be minimized by increasing the number of classes.
Natural Breaks: Classes are based on natural groupings of data values. Natural break points
are identified by looking for groupings and patterns inherent in the data. The features are divided
into classes whose boundaries are set where there are relatively large jumps in the distribution of
data values.
* EMAP-West Landscape Metrics Metadata (FGDC)
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