The Ceiling and Visibility Plot is intended to aid situational awareness with a quick-glance visualization of current ceiling and visibility (C&V) conditions across an area or along a route of flight. Common IFR producers are low clouds (stratus), haze, smoke, blowing obstructions to vision, and precipitation. Fog and low stratus restrict navigation by visual reference more often than all other weather phenomena. The Ceiling and Visibility Plot derives C&V for areas between METAR stations and so it may, as a function of distance from a METAR, misrepresent actual conditions. Therefore, the chart should always be used in combination with ceiling and visibility information from official sources such as METARs, AIRMETs, and TAFs.