If we have a plot with a continuous date/time X axis, but without values for every value of the X axis, we should be able to specify a default value for the Y axis if there is no data for a point on the X axis. Right now, Spotfire will carry on the line in the line graph (instead of showing 0) or not put a bar in place, or similar.
See here for a couple of community posts on this:
https://community.tibco.com/questions/show-missing-data-0-and-line-drop-line-chart#node-686301
https://community.tibco.com/questions/replacing-empty-values-zero#node-694476