A new method for line image vectorization based on a partition-and-merge technique is presented in this paper. A shape is first partitioned into a set of non-overlapping triangles by the constrained Delaunay triangulation. Then the initial partitioning is refined to produce a more accurate result. The vector form of the shape is represented by its skeleton, which can be obtained from the skeletons of the parts of the shape. The skeleton thus obtained conforms to human perceptions of the particular shape and can be used to reconstruct the shape.