A method for finding shortest paths is disclosed which uses a piecewise
linear cost model to guide the search of through a compact tile graph and
to ensure that a shortest path may always be found in a computationally
effective manner. Cost function propagation from tile segment to tile
segment is used to search for a target location from a source location
through a region, and the shortest path is found through tracing
backwards using the cost functions calculated during the searching.
Linear minimal convolution is used to facilitate the cost function