Political Causeway: UK Election Results

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 visualise 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 colours 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, organised into four layers with the winners on top and colours 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

Build the grids

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

Download DGGRID software
Build the layers

Extrude and convert 2D features to 3D multipatches to build up the layers. Different base height settings allows you to stack them on top of one another. Create a final layer of capstones using nested extruded polygons and position on top of the four main multipatch layers.

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Design labels to report detailed results

Extrude the legend and leader lines as multipatches. Position billboarded labels at the tip of the leader lines and design popups to report detailed results when the tip of the leader line is clicked.
Put finishing touches on layers

Publish the different layers as web scene layers from ArcGIS Pro to Portal for ArcGIS. Configure layers and organize to support easy switching on and off in the app.

Web scene layers

Data and software

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. Software used: ArcGIS Desktop, ArcGIS for Server.
Analysis

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.
Time

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

Less curve makes your map easier to read

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.
Encode different ways to view the data

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.
Add additional ways to see results

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.
Use an equal area projection

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.
Use an equal area projection

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.
Compensate for curved surfaces

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