1. A method of generating a digital road map, comprising: a first step of collecting a plurality of pieces of track data obtained by a movement of a vehicle; a second step of extracting feature points of the plurality of pieces of track data for a road from which the plurality of pieces of track data are collected to calculate a Spline curve satisfying the extracted feature points; and a third step of adding the calculated Spline curve as a lane central line to the digital road map to update map data.