Birds vs Aircraft by Month

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Why We Love It

A coxcomb chart (first used by Florence Nightingale) is a great way to display multiple facts at one location over time. We love how this map shows quantity and seasonal variation as part of the display, so you don’t have to use pop-ups or multiple maps to get a full picture of bird-related airstrikes on civilian aircraft. The graphic legend is not hidden—a good choice for this map. We also love that as you zoom, the analysis is resampled to create finer resolution coxcombs.

Why It Works

A terrific amount of information is packed into this map. It’s easy to see regional differences and distinct seasonal patterns around the country. Each segment of the coxcomb diagram represents a unique time period and quantity. Because the sectors all have the same angle, they are visually equivalent when used to represent area. This makes the chart easy on the eyes, and the multiple wedge-shaped proportional symbols help us understand differences in quantity.

Important Steps

Creating the coxcomb diagram requires a custom tool that you can download from here.

Once you’ve downloaded the coxcomb tool you can launch it from within ArcMap.

This workflow assumes you have an individual record for each of the components in your chart and a variable that acts as a grouping variable (e.g., all records grouped as one will be represented in one coxcomb, and so on).

Find details of how to use coxcombs to map time here.

Requirements

Data

The size of the coxcomb segments represent magnitudes (counts and amounts) so you’ll need numeric data. The number of segments is the number of time periods.

Analysis

Decide which time periods make the most sense for display in the chart (annual, quarterly, monthly, day of week, day vs night). Knowledge of bird migration patterns may help inform this decision.

Time

Data preparation depends on the size of your data. It will take about an hour to run the coxcomb tool and map the results.

Tips

Instead of using multiple maps or animations, use a coxcomb chart to convey multiple time periods for data that occurs at a coincident point.

Tips

Making a great legend is important. For custom legends, consider adding them to the map view itself as a static image.

Map Author

Kenneth Field

Ken Field

@kennethfield | LinkedIn

Professional cartonerd, amateur drummer and snowboarder. Lifetime encourager of cartographic quality not quantity. Map with the times while building on the past.

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