Used With Routines:  CONTOUR, CONTOURFS

Corresponding System Variable: None.

Specifies that contour paths are to be interpolated using cubic splines.

Use of this keyword implies the use of the Follow keyword. The appearance of contour plots of arrays with low resolution may be improved by using spline interpolation, which can result in smoother lines. In rare cases, contour lines that are close together may cross, or spurious wiggles may be generated because of interpolation; in these cases, increasing the default spline value, as described below, can help.

Splines are especially useful with small data sets (less than 15 array dimensions). With larger data sets the smoothing is not as noticeable and the expense of splines increases rapidly with the number of data points.

You may specify the length of each interpolated line segment in normalized coordinates by including a value with this keyword. The default value is 0.005 which is obtained when the parameter Spline is set to 1, or is entered using '/Spline'. Smaller values for this parameter yield smoother lines, up to the resolution of the output device, at the expense of more computations.