You searched for: Author United States. Environmental Protection Agency Remove constraint Author: United States. Environmental Protection Agency Access Public Remove constraint Access: Public Place Nebraska Remove constraint Place: Nebraska Place Arkansas Remove constraint Place: Arkansas Year 2003 Remove constraint Year: 2003
2003. United States. Environmental Protection Agency. This polygon shapefile shows Omernik's Level III ecoregions, derived from a 1:7,500,000 map created by J.M. Omernik in 1987 and from refinements of... National Atlas of the United States.