The construction area of the base refers to the construction area occupied by buildings, including buildings, courtyards, roads, parking lots and other ancillary facilities and public areas such as green belts. The calculation of base area is generally determined according to planning and design requirements, topography and other factors. The floor area ratio refers to the ratio of the total construction area above the ground to the basement area, that is, the ratio of the total construction volume to the basement area. Height and density of buildings usually used for planning, designing and supervising construction projects. The formula for calculating the floor area ratio is: floor area ratio = total construction area ÷ occupied area of the base.