Oceanic Oscillations
The World’s Tides at Their Greatest Ranges
For a long time, I had wanted to create a map of global tidal range. The idea was loosely inspired by John Nelson’s glacier recession visualizations — a single, striking surface that reveals a global process at a glance. Initially, the plan was much narrower: I assumed the Bay of Fundy would be the star of the show, and I struggled to find data that would let me explore the idea beyond a regional example.
That changed when I started digging through the ArcGIS Living Atlas and discovered a global tidal range raster derived from FES2014 data. While the original Aviso+ datasets would have been a major technical hurdle to process and interpret on my own, Keith VanGraafeiland at Esri had already done the heavy lifting to make the data purpose-ready. That opened the door to treating tidal range as a truly global phenomenon rather than a collection of local curiosities.
I chose the Spilhaus projection deliberately. By presenting the world’s oceans as a single, continuous body rather than something broken at the map edges, the projection reinforces the idea that tides are a connected, planetary-scale system. Because Spilhaus warps continental shapes in ways that can be disorienting, I added coastline labels and callouts to help viewers anchor themselves, along with annotations highlighting regions with exceptionally large tidal ranges.
One of the most surprising outcomes was seeing just how uneven tidal range is across the world. Growing up on Canada’s coast, I had internalized tides as a constant presence everywhere. The vast areas of minimal tidal variation visible in the map challenged that assumption and became one of the most compelling takeaways.
Label placement turned out to be the most technically demanding part of the project. With many regions of interest competing for space, I used ArcGIS Pro’s automated labeling as a starting point, then manually refined nearly every label to balance clarity, hierarchy, and visual calm.
The finished map was later featured by maps.com and in Esri’s ArcUser magazine, and has been used as an example of how careful projection choice, restrained color, and thoughtful annotation can turn a complex geophysical dataset into something accessible to cartographers, students, and the general public.
2024-08-28