Level III Ecoregions of Virginia

Ecoregions by state were extracted from the seamless national shapefile. Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and...各州对应的生态区（Ecoregions）数据从无缝衔接的全国矢量形状文件（shapefile）中提取得到。生态区指的是生态系统、生态类型与质量等方面具备总体相似性的区域……