Level IV Ecoregions of Massachusetts

Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...按州划分的生态区（Ecoregions）从无缝衔接的全国形状文件（shapefile）中提取得到。生态区指的是在生态系统及其类型、质量等方面具备普遍相似性的区域。