Methodology and Interpretation
FPATDENS - Forest patch density
Forest patch density is calculated as the number of forest patches divided by
3 km grid cell reporting unit area in km2. 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 increasing 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
* EMAP-West Landscape Metrics Metadata (FGDC)