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I mapping the number of Boko Haram victims in each state of Nigeria for several years. I chose to make a proportional symbol maps using the centroid of each state. For a given year, the area of the circular symbol is directly related to the number of deaths.

Using ArcMap's proportional symbols symbology does the job, but I have a problem with the legend: enter image description here

The default legend offers me 3 categories which are not very convenient (1, 100, 10.000). I would like to be able to change the breaks in the legend to, say, 100, 1.000, 5.000, 10.000.

Is there a way to do this?

  • Does your data contain values other than those you're interested in showing? More specifically, are all of your data generalized into one of the ranges that you mentioned, or do you have a lot of intermediate values (297, 3530, 17)? – JWallace Feb 16 '15 at 21:07
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    I ask because proportional symbols can become pretty tricky to decipher if they are representing a lot of values - you may be better off using graduated symbols if you have just a few ranges that you want to convey. Graduated symbols offers you the ability to define class number, breaks, etc. – JWallace Feb 16 '15 at 21:09
  • Thank you for your comment. I only have like 20 observations, so I guess it's a bit too few to go to graduated symbols. Also, I think proportional symbols are more adequate since I don't want to show classes of values (i.e. create groups), but I want to have a taste of the amount of deaths at each point. – Damien Feb 17 '15 at 8:25
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In the legend wizard, on the last step you will be prompted with spacing options. Recreate your legend and change the "Spacing between patches (Vertically)" until you find a spacing you like.

In terms of creating more breaks, you have to go to the layer properties and select Symbology > Quantities and modify the number of classes.

enter image description here

  • The screen that you're showing here is for Graduated Symbols. The Proportional Symbols does not offer the Classify options as shown here - that is why I was trying to see if using graduated symbology would work for OP's purposes. – JWallace Feb 17 '15 at 16:41
  • Ah, I missed that. It seems as though what OP is trying to achieve can be done using Graduated Symbols, which offers the same class break options as the Graduated Colors option. The OP can do custom breaks for Graduated Colors and then modifying the label, giving it the same visual appearance as the proportional symbol. – Alex McVittie Feb 17 '15 at 18:12
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Just convert your legend to graphics, ungroup until it's all separated (you may have to do it several times) and manually edit the circle's size and labels.

Then play a little with the "align" and "distribute" tools to make it look nice and centered.

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