The weighted Gauss-Seidel-progressive iterative approximation (WGS-PIA) algorithm for cubic B-spline curve interpolations is considered in this paper. The convergence of the WGS-PIA algorithm is analyzed, and an upper bound whichis strictly smaller than one for the contraction factor of this WGS-PIA algorithm is derived. It is shown that for cubic B-spline curve interpolations, the GS-PIA algorithm converges fa...