Why to use logarithmic scales and with what software?
A logarithmic chart can be useful when you want to display data with big difference in numeric values in a chart. In the example I attached, with and without the logarithmic scale, you can see that the reader, with the regular view, cannot identify values and difference with a reasonable degree of accuracy until 1993. Using the logarithmic scale improve the resolution of the individual data points.
The chart I’m showing is Oracle, and they almost went bankruptcy in 1990. You will not see that in the linear chart.
Of course, the biggest problem is that as a whole, it will not give a correct idea of the performance of a stock (to stay with the same example). And readers are not used to this kind of charts.
I think it is OK to use it, in exceptional occasions that justify it, and as long as we make sure to highlight the fact we are using this system. And maybe it would be good to use the usual one (linear) as a small reference chart in the same graphic.
If one of you guys want to try it, you would have to use Deltagraph.
