Level IV Ecoregions of Maine

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）从无缝拼接的国家级shapefile文件中提取得到。生态区指代生态系统、生态类型与质量等方面具备整体相似性的区域。