Reference to the lowpass() function


lowpass(<expression1>, <expression2>[, inner])

Returns only the points in expression2 that are below expression1. expression1 is often a constant. Specify inner if you want an inner join.


expression1 Threshold expression. Often a constant.
expression2 Expression that you want to filter.
inner Results in an inner join.


The lowpass() filtering function plots a chart based on all reported data values that are lower than the specified threshold. The function discards data values that are greater than or equal to the threshold, resulting in gaps of missing data between the remaining points.


lowpass example

In the example chart above, solid orange lines are only present when the reported data values are lower than the threshold. In this example, the threshold is 140. The remaining reported data values display as dashed lines to indicate missing data.

See Also

Series Matching