How do I plot chart with negative value using Logarithmic Scale ?

[FTian]

[Del Cotter]

On Sun, 14 May 2006, in microsoft.public.excel.charting,
FTian <[email protected]> said:

[no content, but Subject line reads: "How do I plot chart with negative
value using Logarithmic Scale ?"]

It's not Excel's fault you can't do that, it's a mathematical
impossibility. Zero is an infinite distance way down past the bottom of
the chart, and negative numbers are "beyond infinity".

If you still want to try it, then you need to use a linear scale, but
create a column with a formula that looks like:

=IF(x<0,-LN(-x),LN(x))

and plot that instead. Then go to Jon Peltier's site and learn about
using "dummy axes", ranges of labelled data that are created to mimic
the appearance of an axis in Excel, to do what Excel's axes can't do.

Then you should put a text box in the chart to explain to the readers
that what they're seeing is not a proper log scale, but two log scales
back-to-back, one for positive, and one for reversed negative.

--
Del Cotter
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