Putting voter turnout on the map

Data visualisation
2010 general election voter turnout
2010 general election voter turnout

With a general election less than one month away the news will soon be filled with election predictions and statistics. Such election data is a perfect subject for a project I am currently working on at BrightLemon. The aim of this project is to create a data visualisation tool that can display big datasets in innovative and interesting ways. These data visualisations will be easy to share and accessible to all users.

Presently, I am working on maps with areas coloured to represent a different value depending on where it falls on a scale. The technical term for this kind of data visualisation is a choropleth. There are some complex mathematics involved in generating a choropleth: automatically computing the scale from the uploaded data, projecting the spherical earth as a flat map etc. Fortunately, D3, which is at the core of the tool I am building, has functions to handle all of these tasks.

The map, above, is divided into Westminster parliamentary constituencies, which will be the battlegrounds for the parties hoping to win on 7 May. The dataset used is the voter turnout for each of the constituencies during the last election in 2010. At a glance, it appears that less people turnout to vote in the cities and, generally, slightly more people in the south of England.

Data source: The Electoral Commission