topic Re: Help with Proportional Symbology in Data Management Questions

Help with Proportional Symbology

TracyHutchens — Thu, 29 Aug 2013 19:48:19 GMT

I i am creating a map using proportional symbology and i have sales of different kinds of rock in my tables. I copied the shapefile so i could have one layer for each type of rock then symbolized that layer with proportional symbology. The size of my circles that arc map gave me are all different and are not proportional to each other. For example I have 100,000 of one type of rock and 50,000 of another, but the circles are not half the size. Am i making sense, can anyone help me?

Re: Help with Proportional Symbology

JimCousins — Fri, 30 Aug 2013 13:35:13 GMT

This is because you are letting ArcMap decide the break points for your classification symbology. Take the layer with the highest value, and manually set the break points you want for all layers. When you have that configured, either save that as a lyr file and then import it for the symbology of the other layers, or choose import >> and select that first layer. This will keep the same class breaks, descriptions, and size for all your features.
Regards,
Jim

Re: Help with Proportional Symbology

TracyHutchens — Wed, 25 Sep 2013 16:14:22 GMT

How do I manually set the break points? is it in the classification?

Thank you!

Re: Help with Proportional Symbology

JimCousins — Mon, 30 Sep 2013 14:09:34 GMT

Sorry for the delayed response, Tracy, I have been out of office.
You are correct, one can not set the break points in the proportional symbology interface.
I would create a "fake" dataset that covers the full range of values from all layers you wish to symbolize (unless one already covers the full range), create the symbology for that dataset, and use that for the symbology template.
Regards,
Jim

Re: Help with Proportional Symbology

TrishRice — Mon, 30 Sep 2013 20:02:49 GMT

Instead of proportional symbols try graduated symbols. The differences escape me but graduated symbols let you manually set the breaks.

Alternatively you can abuse pie charts. Select only one field so that you get a circle that is all one color, and tell it to vary the size based on a field (quantity of rock sold). That should get circles that are proportionate to each other.