visualizing multiple data sets

Occasional Contributor

Sometimes I want to be able to see multiple data sets, which have the same basis (time, for example), on the same chart.

 

For example, lets say I need to see some engine data over time: RPM, temperature and fuel trims. (and possibly more) It's useful to plot them on the same area, so you can visualize, and directly compare, how the value change at various moments in time. The challenge of course, is that while each series shares the same X-value (time), they may have vastly different ranges (y-value). RPM are usually in the thousands. Temp will usually be up to 100, and trims are percentages in the range of -30% to +30%. If you tried to plot them on the same Y-axis, you would get a very ugly graph that wasn't useful visually. Excel does provide a secondary axis, so you can in fact work with up to two value ranges.

 

I was wondering if anybody knew some strategies, or clever tricks for working with more than two data sets. Of course I could stack multiple charts aligned vertically, but it's not as nice as having them together. Or does there exist more powerful software that can better handle data plotting?

1 Reply

@mountainmanjoe 

I would not recommend combining many data sets, it does not improve the readability of the chart.

But you could use formulas to divide RPM by 1000 or 10000, and plot it on the same axis as temperature, and plot fuel trims on the secondary value axis.