1. A method of determining anisotropy in a borehole comprising: obtaining an array of measurements along the borehole; selecting a first depth in the borehole; designating an arbitrary plane oriented with respect to the borehole at the first depth; determining an anisotropy for the first depth with respect to the arbitrary plane; repositioning the arbitrary plane at the first depth; determining an anisotropy for different positions of the arbitrary plane at the first depth; identifying a minimum anisotropy coefficient with respect to the arbitrary plane at the first depth; wherein the minimum anisotropy coefficient is identified based on anisotropy for different positions of the arbitrary plane; defining an anisotropy tensor for the first depth.