1. A method comprising, at a mobile device: receiving one or more data files comprising: an encoded routability graph corresponding to an indoor environment represented by an encoded map, said encoded routability graph being indicative of a plurality of feasible paths within said indoor environment, said plurality of feasible paths being indicated, at least in part, by junctions selectively interconnected by edges, and a plurality of values indicative of likelihoods of transition for at least one of said junctions, said at least one of said junctions being connected to three or more of said edges, wherein said likelihoods of transition are based, at least in part, on one or more features of said encoded map, one or more predetermined possible origination paths in said encoded routability graph leading to said at least one of said junctions via one of said three or more of said edges, and one or more predetermined possible destination paths that lead away from said at least one of said junctions via at least two of said three or more of said edges; and determining at least one of an estimated position of said mobile device, or an estimated direction of travel of said mobile device based, at least in part, on at least one of said plurality of values indicative of likelihoods of transition and said encoded routability graph.