1. A method of computing local conduction velocity of a cardiac activation wavefront, comprising: collecting a plurality of electrophysiology (“EP”) data points using a multi-electrode catheter, each EP data point of the plurality of EP data points comprising position data and local activation time (“LAT”) data; repeating the following steps a plurality of times, thereby computing a plurality of conduction velocities: selecting an EP data point from the plurality of EP data points; defining a neighborhood of EP data points including the selected EP data point and at least two additional EP data points from the plurality of EP data points; and computing a conduction velocity for the selected EP data point using the position data of the EP data points within the neighborhood of EP data points and the LAT data of the EP data points within the neighborhood of EP data points; and outputting a three-dimensional graphical representation of the plurality of conduction velocities, wherein the graphical representation includes a plurality of conduction velocity vector icons arranged in a uniform grid over a three-dimensional model of at least a portion of a heart.