The work includes a comparative study of several contouring methods for univariate surfaces. It focusses specially on the comparison of the algorithms for the interpolation of irregular data sets (triangular Shepard, Powell & Sabin, Clough & Tocher). They are discussed in terms of smoothness and precission of the curves, amount of storage and computing time. Methods for the generation of the contours, clipping against the boundaries and writing legends are also discussed briefly.