Rather than map raw data, cartographers often use GIS to merge or join features to show larger patterns, calculating counts or averages and other statistical measures expressed by area, time, or per capita.
We love it when cartography makes sense of complicated data. This map delivers, showing thousands of tornados averaged over time and space to reveal seasonal and regional patterns. The legend uses color to denote month, and size to show tornado intensity. We see the timing of peak tornado activity through animation. The rings, color-coded by season, keep us fixed on the map instead of the legend. We learn that some places have year-round tornado risk, while others are limited to summer months. A looping animated GIF emphasize the fact that tornados occur as a cyclical, annual process.
Animated data really makes this map work. It draws focus beyond individual circles to the aggregate effect of circles synchronizing, blooming, and changing in waves. Just as when we watch a flock of birds, we no longer see individual birds. We abstract them into a simpler, larger visual object—a flock. With animated maps, hundreds of disparate symbols become a single, organic shape that shows both location and rate of change. This map is a great example of how animation can clarify a complicated dataset and nuance our understanding of geographic processes playing out over space and time.
I have way too much fun looking for ways to understand and visually present data, engage others, and write about it. Otherwise, I’m chasing around toddlers and wrangling chickens. Life is good.
If you liked this map, check out these other Maps We Love that explore similar topics.