Imagine automating the motion of a lawnmower for an estate that has many obstacles, such as a house, trees, garage, and a complicated property boundary. What are the best zig-zag motions for the lawnmower? Can the amount of redundant traversals be minimized? Can the number of times the lawnmower needs to be stopped and rotated be minimized? This is one example of coverage planning, which is motivated by applications such as lawn mowing, automated farming, painting, vacuum cleaning, and mine sweeping. A survey of this area appears in . Even for a region in , finding an optimal-length solution to coverage planning is NP-hard, by reduction to the closely related Traveling Salesman Problem [36,709]. Therefore, we are willing to tolerate approximate or even heuristic solutions to the general coverage problem, even in .