USDAPLNTZONES
(source 1 of 1)
U.S. Department of Agriculture, Natural Resources Conservation Service, 20060501, USDA Plant Hardiness Zones Map.
Type of source media: online
Source contribution:
The USDA is pretty confident that this digital file was"heads-up" digitizing from a JPG version of 22 or 26 plates of an original hardcopy map.