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Methodology and Interpretation
RNAT0 - Percent all natural land use adjacent to streams
The percentage of natural land cover adjacent to streams is calculated by
summing the total number of forest, shrub land, grassland, wetland, and bare
rock land cover cells underneath stream segments in the 3 km grid cell reporting
unit and dividing by the stream corridor's total land area (total number cells
underneath stream segments minus those classified as water). High proportions of
natural land cover may be an indication of little human influence in the watershed,
but provides no information on the health of the vegetation cover.
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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