You searched for: Publisher National Atlas of the United States Remove constraint Publisher: National Atlas of the United States Access Public Remove constraint Access: Public Subject Biology and Ecology Remove constraint Subject: Biology and Ecology Place Massachusetts Remove constraint Place: Massachusetts Data type Polygon Remove constraint Data type: Polygon 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.