Sectional Aeronautical Charts are the primary navigational reference medium used by the VFR pilot community. The 1:500,000 scale Sectional Aeronautical Chart Series is designed for visual navigation of slow to medium speed aircraft. The topographic information featured consists of the relief and a judicious selection of visual checkpoints used for flight under visual flight rules. The checkpoints include populated places, drainage patterns, roads, railroads, and other distinctive landmarks. The aeronautical information on Sectional Charts includes visual and radio aids to navigation, airports, controlled airspace, restricted areas, obstructions, and related data. These charts are updated every six months, most Alaska Charts annually.