In 2008, the boundaries of deer winter areas where refined using black and white leaf-off 1:5,000 scale orthophotography (1990-1999) and was cross referenced with 1:24,000 scale 2003 NAIP (color, leaf-on) imagery to better delineate fields and open wetlands. Some of the areas were also marked as 'not likely wintering area' based on not having softwood characteristic. The areas were reviewed by VFWD District Biologists in 2009 to 2010 for their concurrence from their knowledge of the site. The 2008 mapping project did not involve any field work, but was based on aerial photography. Potential areas were identified, but they have not been included in this map layer because they have not been field verified.
The original DWA mapping was done in the 1970s and early 1980s and was based on field visits and interviews with wildlife biologists and game wardens. The DWA were mapped on mylar overlays on topographic maps and based on small scale aerial photos.
VIP, formally the VT Mapping Program for some source data, and its contractors validated that the data meets National Map Accuracy Standards for 1:5000 scale imagery, which equals about +- 5 meters.