Table 2 Input data by type, source, and temporal and spatial resolution.
Feature | Spatial Product | Years | Urban Proxy Definition based on… | Resolution |
|---|---|---|---|---|
Census geography-Urban People | US Census blocks | 1990 | Population density and count, proximity: jumps up to 1.5 miles | Variable (delineated by man-made and physical features of the landscape) |
2000 | na | |||
2010 | Population count, density, land-use; proximity: hops up to 2.5 miles | |||
OMB geography-Commuting Area | Metropolitan Statistical Areas | 1990 | Population count, population density, employment connectivity (commuting) | Variable (mainly delineated by county and aggregate county boundaries) |
na | ||||
2010 | ||||
Satellite-based urban proxies-Urban Land | Global Human Settlement Layer | c. 1975, 1990, 2000, 2014 | Measure of built-up land cover. Urban extents are constructed based on grid cell values meeting a 25%, 40%, or 50% built-up threshold. | original: 30 meters original GHSL, aggregated: 250 meters |
