Physiographic divisions of the conterminous U. S.

This is a polygon coverage of Physiographic Divisions in the conterminous United States. It was automated from Fenneman's 1:7,000,000-scale map, "Physical Divisions...本数据集为美国本土（conterminous United States）地貌分区（Physiographic Divisions）的多边形覆盖数据集。该数据集基于芬纳曼（Fenneman）编制的1:700万比例尺地图"Physical Divisions..."经自动化处理生成。