To tell RainPro to ignore specific values:

chSet 'Missval' 0

The default setting is 32768. The effect of setting it to zero is to make line graphs skip over zero values, rather than drawing an annoying line down to the axis wherever zero is hit. When you plot an array of data with differing numbers of elements, RainPro automatically pads the shorter series with the current missing-value setting. If you pass an array of values, all of them will be automatically excluded:

chSet 'Missval' ¯1 ¯99

This might be appropriate for data from some logging device, where a variety of negative numbers indicate various error conditions.

By default, line-graphs simply ‘bridge’ the missing points by joining the points on either side. Use the segmented style to have the line broken wherever data is missing.

See also ...
Not Applicable – placeholder for missing value