1. A method for mapping an anatomical structure, the method comprising: sensing activation signals of intrinsic physiological activity with a plurality of mapping electrodes disposed in or near the anatomical structure, each of the plurality of mapping electrodes having an electrode location; determining a dominant frequency for each sensed activation signal at each electrode location; determining a plurality of difference vectors at each electrode location, wherein a difference vector of the plurality of difference vectors for a respective electrode location represents a difference between the dominant frequency of a sensed activation signal at the respective electrode location and the dominant frequency of a sensed activation signal at a neighboring electrode location; and determining a wavefront vector at each electrode location based on the plurality of difference vectors.