Hi:
Mathematically, what's the value of log(-1)? So it's impossible to use the real logarithm axis.
So I supposed your data is in a really wide range and you want to plot them tight. An workaround as below:
Column A and B are raw data, and the other columns are:
Col(C) = -log(-Col(A));
Col(D) = Col(B);
And Column E is just the same data from Column A, but sort ascendingly. Then we will use this column E as axis ticks. Plot column C & D, and double-click the X axis to bring up X Axis property dialog. On Tick Labels tab, use Tick-indexed dataset Type and assign column E to Dataset drop down:
Then you will get something like:
Note that it's not really log scale. The scale still linear, but we use different tick labels.
Hope it helps.
Thanks
Larry
OriginLab Technical Services
log10 scale and negative values
Posted - 10/22/2009 : 07:13:52 AM
