How to make Proportionally Sized Pie Charts

Hello all,

I am trying to put together two pie charts to represent sales for two corresponding years. One year has higher sales than the other, and I would like to show that with the physical size of the pie charts. Is there an easy way to have the diameter or total area of a pie chart correspond to a specific number?

For example, if the sales for year 1 were $200 million and sales for year 2 were $100 million, is there a way to make chart 1 appear exactly 2 times larger (area) than the pie chart for year 2?

It sounds simple, but some searching on the internet has made it sound like this is not easy to do. Thank you for any help!

Anyone have any ideas, or is it really that difficult?

It seems like it should be quite an easy implementation for Microsoft to include, and it's really surprising there is not some formatting spot that this can be done through.

Originally Posted by JosephP

in my opinion pie charts are not the right chart for this kind of comparison (they're rarely the right chart for anything) which is one reason there isn't a one-click answer. it sounds like a bar or column chart would be a much better proposition

Hi Joseph, thanks for the reply.

I would wholeheartedly agree, but the company I work for has their mind set on pie charts for their presentation. Regardless, I think it's something that should be added to future Excel functionality if it really does not exist currently.

I ended up manually changing the chart sizes and approximating the areas which was annoying, but I will check back to see if anyone here knows a way to do it properly!

Originally Posted by JosephP

I guess we'll agree to disagree on that-I really think that should never be added. it's bad enough that pie charts exist without encouraging people to use them in this way ;-) if they do add it it should be under a new 'absolutely not recommended charts' group

Interesting view on that. Not sure why you want to limit anyone from doing anything they would want to do to present data as they see fit or, more importantly often, as their boss(es) see fit. I'd rather have too many options than too few.

Originally Posted by JosephP

notwithstanding the above I reckon this code would get you started

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Thank you sir, I will take a look and see what I can do with it. Very much appreciated!

-Eric

Originally Posted by Andy Pope

JP's comments not withstanding see the pie by pie example.
http://www.andypope.info/charts/pies.htm

You can then adjust, within reason, the size of each pie.

Thanks Andy, just curious, what is your overall opinion on pie charts? I think they're great for certain things, and not so great for other things (just like any chart really).

I am doing a course at the moment where we have to do what you are asking.
We have to produce a number of different pie charts of different sizes, so that the areas of the different charts are proportionate to the total value they are representing.
The way I understand it is that the square root of the total value represented by the chart is proportionate to the radius of the circle.
So.. if you had chart A representing a total of $90,000 and chart B representing a total of $40,000 you would take the square root of both those values.
The square roots would be 300 and 200 respectively.
So you would make the radius of the charts proportionate to those values.
Chart A could have a radius of 3cm and chart B could have radius of 2cm - and this should make the areas of the charts proportionate to the values being represented.
Hope that makes sense...

I'll paste the relevant section from my course materials below:

Construction of proportional circles
Designing proportional circles is an exercise in fitting the symbols into the available space. How large
the symbols can be depends on how many are to be shown and the size of the paper to be used. There
is also a constraint on the minimum size, especially if the circles are also to be divided up as pie charts.
Usually, a one centimetre radius is about as small as can conveniently be drawn. Let us assume we wish to draw three proportional circles to represent a firm’s annual sales over a three
year period. 1984’s value is $205M, 1983 - $150M, 1982 - $501M.
If we decide to let a circle with a radius of 1 cm represent $100m, then the radii of the three circles can
be determined as follows:
$100M
12
=
$205M
X2
The solution for X = 1.4 cm.
That is, the circle to represent 1984’s sales would be 1.4 cm in radius.
Solution: $100M
12
=
$205M
X2
Cross–multiply: $100M . X2
=12. $205M=$205M
Divide both sides by $100M: $100M X2
$100M =
$205M
$100M
X2
=2.05
Take the square root of both sides: X2
= 2.05
X=1.4
The size for 1983 is:
$100M
12
=
$150M
X2
X=1.2 cm
For 1982:
$100M
1
2
=
$501M
X2
X=2.2 cm