Reference to the interpolate() function



Fills in gaps in the expression with a continuous linear interpolation of points.


expression Expression in which you want to replace gaps in data with the next value.


The interpolate() function replaces a gap of missing data (dashed line) with a solid line. The value assigned to the new solid line depends on where the interpolation occurred in relation to the value on the y-axis.

For example, suppose there is a gap of missing data in between two reported point values of 2 and 1. The value assigned to that gap of missing data will be between 2 and 1, with the displayed value dependent on where it intersects the y-axis. When Wavefront performs interpolation, it applies interpolate() to the first 85% of a chart window.


The following example zooms in on an area of a chart where data are missing. Wavefront uses dashed lines to indicate the missing data.

interpolate before

When you use interpolate() for this use case, the dashed lines are replaced with filled lines, indistinguishable from areas where data are available.

interpolate after

See Also

Using Moving and Tumbling Windows to Highlight trends

Other missing data functions include default, next, and last.