Dots are aggregated by and placed randomly within 8-digit hydrologic units. Each red dot represents 2,000 acres of rangeland converted to developed land.
Developed land is a combination of urban and built-up areas and rural transportation land.
There were 3,281,300 acres of rangeland converted to developed land from 1982 to 1997. Within an 8-digit hydrologic unit, dot counts represent total acreage, with an error of plus or minus one dot to account for remainders. Data are not available for Alaska or the Pacific Basin. Data for Puerto Rico and the U.S. Virgin Islands are aggregated by 6-digit hydrologic unit. NRI maps reflect national patterns rather than site- specific information.