feature request: logarithmic axes

[tobyink]

It would be useful to be able to generate charts with a Y axis like this:

10000 -
 1000 -
  100 -
   10 -
    1 -

Axes like that are useful for charts where there are a handful of extreme peaks, but lots of interesting low-level activity.

[gphat]

I might get around to this soon. :)