When it comes to specific scales in planning, certain objects may have to be drawn (quasi) to scale, while others may only be presented in symbolic fashion. For example, requirements may call for a layout plan to include a derail unit on the scale of 1:500 being presented twice as large as on a scale of 1:1000 and for an overview plan to include the same unit on a scale of 1:5000 being presented not half as large, but rather exactly as large as on a scale of 1:2000. Insertion factors would then need to be selected accordingly.