USM toolset (Urban Sprawl Metric toolset)
The USM Toolset calculates Weighted Urban Proliferation (WUP) and its components (PBA, DIS, LUP) for user-defined reporting units. Includes three algorithms: full WUP calculation from a built-up area raster, re-use of a previously computed SI raster for new reporting units, and interactive exploration of WUP from existing field values.
Weighted Urban Proliferation (WUP) has three components: PBA, DIS, and LUP (or UD). Proportion of built-up areas (PBA) is the ratio of the size of built-up areas to the size of the landscape (reporting unit): PBA = Area of built-up area / Area of reporting unit. Degree of urban dispersion (DIS) measures the dispersion of built-up areas based on the distances between any two points within the built-up areas. DIS is expressed in urban permeation units per square meter of built-up area (UPU/m^2). More dispersed built-up areas have higher DIS values. Land Uptake per person (LUP) is the area of land used per inhabitant or job within the built-up areas, expressed in square meters per inhabitant or job (m^2/(inh. or job)). High LUP values indicate more space used per inhabitant or workplace. LUP is the reciprocal of UD: LUP = 1/UD.