Creating Pie Chart in Legend with Varying Representations of Percentage using ArcGIS for Desktop?

Decoding Pie Chart Legends: Making Percentages Pop in ArcGIS Desktop

Pie charts, right? We all know them. They’re those visual goodies that break down data into easy-to-digest slices, showing how much each piece contributes to the whole pie. And when you’re mapping with ArcGIS Desktop, pie charts can be super powerful for visualizing spatial data. But here’s the thing: a pie chart is only as good as its legend. If your legend is confusing or doesn’t clearly show the percentages, your map loses its punch. So, let’s talk about how to whip those pie chart legends into shape, making sure those percentages jump off the page and tell a clear story.

Pie Chart Basics: A Quick Refresher

Before we get our hands dirty with legend customization, let’s make sure we’re all on the same page with pie charts in ArcGIS. Basically, ArcGIS turns your data into pie slices, with each slice’s size reflecting its percentage of the total. Think of it like dividing up a pizza – each slice represents a different category, and the bigger the slice, the bigger the proportion. Pie charts are awesome for showing the makeup of things, like the different types of land cover in a region or the distribution of age groups in a city. You can make these charts by picking a category or by selecting multiple number-based fields.

Percentage Power: Showing the Numbers

Now, how do we get those percentages front and center in our legend? ArcGIS gives us a couple of cool options:

• Data Labels: These are your go-to for slapping the actual numbers right onto the pie slices. You can show the raw count, the percentage, or both! And the best part? Whatever you set here – value, percentage, or both – shows up not only in the legend but also on the chart itself and in those handy pop-ups when you hover over a slice. It’s all connected!
• Legend Tweaks: For a more polished look, you can customize the legend itself to show percentages alongside the category labels. This takes a bit more finesse, but it’s worth it for a professional-looking map.

The Recipe: Crafting a Percentage-Packed Legend

Okay, so ArcGIS doesn’t have a magic “make awesome legend” button, but here’s a step-by-step approach to create a pie chart legend that really shines:

Pro Tips and Tricks

• Arcade Magic: If you’re rocking ArcGIS Pro, check out Arcade expressions. They let you dynamically display the top field values in a pop-up pie chart legend. Super slick!
• Slice Threshold: Got a bunch of tiny slices cluttering up your chart? Use the slice threshold to group them into a single “Other” slice.
• Label Length: If your labels are getting cut off, crank up the label character limit. You can also choose whether to show the raw value, the percentage, or both.
• Mobile Matters: Keep in mind that data labels can get squished in mobile view. Turn on label optimization and tweak the label offset to make sure everything looks good on smaller screens.
• Alias Power: Make sure your legend uses field aliases instead of the actual field names. It’s way more user-friendly! You can change the alias in the Fields tab of your layer properties.

Other Ways to Skin a Cat

• Fake It with Points: Create a point feature class that mirrors your pie chart data. Apply the same symbology, add it to your map, and then manually move the points around to create a custom legend.
• Draw It Yourself: Get crafty with graphic elements! You can build a legend from scratch using lines, shapes, and text.

The Takeaway

Creating pie chart legends that clearly communicate percentages in ArcGIS Desktop takes a bit of effort, but it’s totally worth it. By mastering the basics, tweaking legend labels, and exploring advanced techniques, you can create maps that are not only visually appealing but also incredibly informative. So, go forth and make those percentages pop! Your audience will thank you for it.