using log scale in a bar chart

I have the following data:

 Week 1 Week 2
------------------
A 0.04 0.5
B 0.2 0.7
C 0.04 1
D 0.4 0.5

Everything looks fine when I tried to plot a grouped column chart:

But after changing to log scale on the y axis it became upside down:

Edit: I would like to show something like my original plot but with y axis ticking at 0.01, 0.1, and 1 (rather than 0.2, 0.4, ...). Is there a way I can do that w/o using logs?

1 Answer

As log 1 = 0, all numbers between 0 and 1 have negative logs, therefore your chart is shown "upside down". If you change one of the values to something greater than 1 you'll see that this value is charted upwards.

The function log10() shows you that the chart is correct (e.g. log10(0.04)=-1.39794).

In LibreOffice you can choose where the drawn columns should begin:

With value set to 1 I get the same as your chart, with value set to 0, I get columns beginning at the bottom of the chart.