The second finding, however, is the key weakness of a log chart: people have a hard time interpreting the scale. In the log chart, the final dot looks like it’s at around 60-70,000 deaths or so.

Logarithmic scales have other advantages as well. Returning to the APPL charts above, it is impossible to imagine drawing a trendline connecting the series of lows in 2003 on up through 2008.

Logarithmic and Arithmetic Scales for Line Graphs Ian A. McKay and Helen E. Parson The Clearing House , pp. 89-93 (5 pages) ...

For our Dow chart, we implemented a vertical timeline (transposing our log scale to the x axis), creating a chart more than 4,000 pixels high.