Political Causeway: UK Election Results

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Why We Love It

We love this map because it takes a cartogram and adds the third dimension for an eye-catching, immersive effect. This 3D hexagonal cartogram imagines a new way to visualize and record election results. It captures the results in a stratigraphy reminiscent of Giant’s Causeway, a geological marvel of interlocking basalt columns in Northern Ireland. The colors of different political parties create a layered landscape. The map legend allows us to strip away layers and explore the results.

Why It Works

Rising upward, the hexagons become columns representing voter turnout, organized into four layers with the winners on top and colors defining political affiliation. A further layer of capstones shows the results as nested, proportional symbols so that, from above, the map can be viewed as a 2D summary. Progressive disclosure of labels reduces clutter and legends. Be sure to switch layers on and off and use the bookmarks to explore specific views.

Important Steps

A set of 650 equal area hexagonal features were generated and attributed with the results of the election. The grids were built using Kevin Sahr’s DGGRID software. The grids were built for the abstract hex-globe and have the advantage of being geometrically accurate across a curved surface.

2D features were extruded and converted to 3D multipatches to build up the layers. Different base height settings allowed us to stack them on top of one another. 

A final layer of capstones, created using nested extruded polygons, was positioned on top of the four main multipatch layers.

The legend and leader lines were extruded as multipatches. Billboarded labels were positioned at the tip of the leader lines and popups designed to report detailed results when the tip of the leader line is clicked.

The different layers were published as web scene layers from ArcGIS Pro to Portal for ArcGIS. Layers were configured and organized to support easy switching on and off in the app.

The final app has bookmarks that takes users to preset views and an information point that gives background information when clicked.



Results for the UK elections were compiled into a spreadsheet as they were reported on election night. These were joined to a dataset of UK political constituencies and subsequently to the hexagonal cartogram.


For this map it was important to ensure the data was formatted so that four layers could be built from the original dataset. It required some summation of various raw numbers in Excel before bringing it into ArcGIS Pro.


Collating data on election night required the most amount of time. DGGRID provides a way to generate discrete global grids. It took a day to edit the grids into the final tessellation of 650 constituencies. Once the layers were published to Portal for ArcGIS, the final map could be built in a few hours.

Extruded Polygons


Placing extruded polygons on a curved surface can make a map difficult to read. It’s better to have a small area with minimal curvature and small variations in height of the columns.

Using 3D to Encode


Here, winners, runners-up, third place and also-rans are layers that can be explored independently thanks to 3D. Using 3D to encode different aspects of the data provides a way to see into the map.

Adding A Layer



Adding a layer on top, so that the structure of the internals of the map can be seen in one go, provides an additional way to see the results.

Providing Clear Bookmark


Providing clear bookmarks, map marginalia, and legends supports the interactivity of the map. When you’re making something different, guide the user as much as you can.

Planimetric Maps


For planimetric maps, it’s important to ensure you use an equal area projection to ensure any hexagonal polygons you build will overlay a consistent area across your map.

Hexagonal Shapes


When using hexagonal shapes across a curved surface you should build a discrete global grid..

More Information


2015 - Google award for best mapping of the 2015 UK General Election

Map Author

Ken Field

Ken Field

@kennethfield | LinkedIn

Professional carto-nerd, amateur drummer and snowboarder. High quality, innovative, and sometimes a little crazy cartography in modern maps.

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