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 Metrics > Landscape Characteristics > Metric Map (pfperf9), Natural Breaks, Methodology and Interpretation
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Methodology and Interpretation

PFPERF9 - Percent 3 km grid cell defined as perforated forest
Percent perforated forest is calculated using a moving 270 meter square window (9 pixels x 9 pixels) across the land cover. When the percent forest in the window is greater than 60%, and greater than the window's PFF9 value, the forest cell in the center of the window is categorized as perforated. The number of perforated 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 PFPERF9. A perforated designation indicates largely continuous forest, and non-forest land cover is clumped. Perforated forest probably provides migration corridors across an area, but may or may not provide suitable interior habitat, depending on the species.

Metric Map (pfperf9), Quantile Metric Map (pfperf9), Natural Breaks

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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