Methodology and Interpretation
RWETL0 - Percent wetland adjacent to streams
The percentage of wetland cover adjacent to streams is calculated by dividing
the number of wetland 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).
Forests and wetlands act as filters, removing pollutants from runoff before it enters
streams. Forests and wetlands also provide habitat for a wide variety of valuable
plant and wildlife 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)