Smooth Line Properties

In a chart that displays lines (Line type or XY type), you can choose to show curves instead of straight lines. Some options control the properties of those curves.

Line properties

Line type

Select Cubic Spline or B-Spline.

These are mathematical models that influence the display of the curves. The curves are created by joining together segments of polynomials.

Cubic Spline interpolates your data points with polynomials of degree 3. The transitions between the polynomial pieces are smooth, having the same slope and curvature.

B-Spline uses a parametric, interpolating B-spline curve. Those curves are built piecewise from polynomials.

Resolution

The Resolution determines how many line segments are calculated to draw a piece of polynomial between two data points. You can see the intermediate points if you click any data point.

A higher value leads to a smoother line.

Degree of polynomials

For B-spline lines optionally set the degree of the polynomials.