Algorithm 790: CSHEP2D: Cubic Shepard method for bivariate interpolation of scattered data We describe a new algorithm for scattered data interpolation. The method is similar to that of R. J. Renka’s Algorithm 660 [ibid. 14, No. 2, 149-150 (1988)] but achieves cubic precision and C 2 continuity at very little additional cost. An accompanying article of R. J. Renka and R. Brown [ibid. 25, No. 1, 78-94 (1999; reviewed below)] presents test results that show the method to be among the most accurate available