Level IV Ecoregions of Michigan

Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...各州生态区（Ecoregions）从无缝全国形状文件（shapefile）中提取得到。生态区指生态系统及其类型、质量等方面具有总体相似性的区域，以及……