Methodology and Interpretation
Percent cropland on slopes greater than 3%
The proportion of each reporting unit that has agriculture "cropland" land cover on slopes
greater then 3 percent is calculated using an overlay. The area where crops and slopes over
3 percent are coincident is summed and divided by total reporting unit area.
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.
Metric input GIS data:
- United States Hydrologic Units (8-digit HUCs) - Metadata
- United States Coastal Change Analysis Program (CCAP) - Metadata
- United States National Elevation Dataset (NED) - Metadata