A method comprises: selecting a plurality of electrodes of one or more stimulation leads, the selected plurality of electrodes defining a two-dimensional region； determining a calibration value for stimulation points defined by the plurality of electrodes； selecting a stimulation point within a boundary formed by the two-dimensional region； identifying points on the boundary that are axially displaced relative to the selected stimulation point； automatically calculating boundary calibration values for identified points, each boundary calibration value being calculated as a linear interpolation of calibration values of a pair of stimulation points determined for the plurality of electrodes； automatically assigning a calibration value to the selected stimulation point that is a summation of the calculated boundary calibration values； and using the automatically assigned calibration value for the stimulation point to control an amplitude of stimulation pulses applied to the patient.
