A technique to automatically determine a shape of a path based on crowdsourced trajectory data is disclosed. Trajectory data is collected for a plurality of crowdsourced paths. The trajectory data for each of the plurality of crowdsourced paths is associated with at least one uniquely identifiable ambient signal. Anchor points may be identified corresponding to a transition in a characteristic of trajectory data of an individual crowdsourced path. Matching may be performed based on analyzing matching patterns of anchor points and evaluating the matches. Various embodiments involve using a linked node structure to represent one or more traces and/or indicate routes in a particular geographical area.