Hierarchical Planning

• As in many other cases, you can take advantage of hierarchy with planning.
• Make a coarse plan, then refine it.
• So, if I want to get from here to the Tower of London, I first make a coarse plan (get to the tube, take the tube to Tower Bridge, get from that tube station to the tower).
• Then I worry about the finer plan.
• You can have multiple levels of planning, and it's usually an efficient way to break down the problem.
• However, when there are lots of interactions with variables, hierarchy may not work.
• This type of planning is particularly complex.