Created attachment 103105 [details]
Example of use as confidence intervals

It should be possible to define column charts with a bottom and a top, without creating a stacked bar chart and making the lower ones invisible (doesn't work for all cases anyway).  Maybe a data structure like this:

Date    Sensor A low    Sensor A high   Sensor B low    Sensor B high
1       1               3               2               7
2       3               5               3               5
3       -4              -1              5               6


and the columns are placed side by side and extend from low to high.