Visual resource inventory visual distance zones are landscapes that are subdivided into three distance zones based on relative visibility from travel routes or observation points. The three zones are foreground-middleground (fm), background (bg), and seldom seen (ss). Foreground-middleground zone includes areas seen from highways, rivers or other viewing locations which are less than 3 to 5 miles away. Seen areas beyond the foreground-middleground (fm) zone but usually less than 15 miles away are in the background (bg) zone. Areas not seen as fm, or bg are in the seldom-seen zone. These data represent the polygon features used to define the vdz.
BLM Colorado Visual Resource Inventory Visual Distance Zone Polygons
Bureau of Land Management Colorado State Office - Dave Taylor