Saturday, 7 September 2013

Guardian's Australian Election Map

Mapping election results usually brings out the worst in cartography.  The usual default is to map an arbitrary area in a single solid colour showing the winner's affiliation (think red/blue US States).  The problem with this sort of approach is the underlying 'real' geography of where people who vote actually live is missing.  The map ends up showing a severely distorted geography because it doesn't take account of the population size and distribution and so the map of US elections appears predominantly red even though Obama (blue) won. The counter is often to distort the geography to equalase the underlying problem..such as creating a population density equalizing cartogram (the so-called Gastner-Newman approach). Then there's the dot density approach, hex-binning approach and the dasymetric approach ad nauseam.

What a refreshing change, then, to see some sense by The Guardian when mapping the Australian election. Nick Evershed briefly touches on some problems with 'traditional' election maps then shows his creation...

It's a sort of Dorling cartogram with circles sized proportional to the population in that electoral area and then coloured according to affiliation.  The circles are displaced to avoid overlapping but they've added a basemap to at least give some geographical sense to the otherwise abstract representation.

I like Dorling cartograms so I am bound to like this effort.  The symbols are clear, efficient and unambiguous. Because of the nature of the population distribution in Australia the map works and the major cities become identifiable (labels would help for people to identify each of the major cities though).  In a country that has far more people crammed across more of the actual space the technique wouldn't be as effective.

I'd have preferred a larger variation in symbol size (it's difficult to see any differentiation) and a legend to tell me what amount of people are represented by the symbol sizes but kudos to The Guardian who have not simply reached for the defaults and have sought to illustrate the story with something more nuanced and thought through. They've actually showed something sadly lacking amongst many of today's rapid map-making map-makers...they've done some cartographic research and made effective use of it. Even better, their write-up briefly describes their design process and explains why other maps were discounted before they arrived at this effort.

Form, function and keeping it simple.  Simple!

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