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.
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.
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.
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.
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.
Data preparation depends on the size of your data. It will take about an hour to run the coxcomb tool and map the results.
Instead of using multiple maps or animations, use a coxcomb chart to convey multiple time periods
for data that occurs at a coincident point.
Making a great legend is important. For custom legends, consider adding them to the map view itself as a static image.
@kennethfield | LinkedIn
Professional cartonerd, amateur drummer and snowboarder. Lifetime encourager of cartographic quality not quantity. Map with the times while building on the past.
A Nation of Drones
Invasive Mussel Species, USA 1998-2013
Diagram of the Causes of Mortality in the Army of the East
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