Methodology and Interpretation
PFINTR9 - Percent 3 km grid cell defined as interior forest
Percent forest interior is calculated using a moving 270 meter square
window (9 pixels x 9 pixels) across the land cover. When the entire window
contains forest cover, the forest cell in the center of the window is classified
as interior. The number of interior forest cells in the 3 km grid cell reporting
unit is then divided by the grid cell's total land area (the total number cells in
the grid cell boundary minus those cells classified as water) to derive PFINTR9.
Interior forest is required habitat for many species.
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
* EMAP-West Landscape Metrics Metadata (FGDC)