The department area is desired area for the department. The area must be smaller than the building area. The sum all department areas must be less than or equal to the building area, which is equal to the product of building width and building depth. The building and department areas should be expressed in compatible units to the building width and depth, i.e., if the building depth and width are expressed in feet then the building and department areas must be expressed in square feet.
You specify the required area for the department. However, various algorithms might create a department with either a continuous or discrete area that is smaller or larger than the specified area.