Spline Charts are quite similar to Line Charts, but there is a function that is
piecewise-defined by polynomial functions, and which possesses a high degree of smoothness at the places
where the polynomial pieces connect (which are known as knots), and this function is used to “smooth” the
corners. Spline chart is used to show changes in time, continuous data that be represented in a table on a
worksheet, like temperature or rates changes.
The difference between line and spline chart is in series display: while the Line
Chart series look like a polyline, Spline Charts’ series look smooth and soft.
This simple spline chart shows rise and fall of the ACME Corp. and its main competitor’s share prices during
one month, there are two series, one for each company. The vertical crosshair
is enabled to see both points in the same category. A tooltip is shown when
any point is hovered; the title of the tooltip is the category name and the rest
of the information (series names and values) is shown in the tooltip body.