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毗邻区域的地貌分区（Physiographic Divisions）多边形覆盖数据（polygon coverage）。该数据集基于芬纳曼（Fenneman）所绘制的1:700万比例尺地图《自然分区……》自动生成。