Further mapping: a win and a near miss

In this post we look at two Divisions from the recent Federal election: the inner city seat of Melbourne, and the bayside seat of Macnamara. Up until the recent election, Melbourne was the only Division to have a Greens representative. Macnamara, previously known as "Melbourne Ports" has been a Labor stronghold for all of its existence.

The near miss: Macnamara

The contest in Macnamara was curious, and the vote counting took a very long time. Unlike almost all other Divisions, in Macnamara it was a three way contest, with Labor, Liberals and Greens polling very similar numbers at each polling booth. In fact the Greens pulled more votes individually than either Labor or the Liberals, but none of these parties had enough first preference votes to win. The decision thus came down to preferences, which knocked out the Greens and in the end put Labor back as the winner. Whether this is a good thing or not depends on your perspective, but it does show that a relatively high first preference count may not necessarily transfer to a win; one of the other parties might pick up more votes through preferences, and enough to push them over an absolute majority of 50% + 1.

But what I decided to do was, similar to my previous mapping post, show the Division of Macnamara with coloured Voronoi regions depending on first preferences. In this map, green shows support for the Greens; red for the Australian Labor Party, and blue for the Liberal Party. (Note that the Liberal Party is not "liberal" in any dictionary sense; this is a right-wing party, once the support of business and economic interests, it has steadily become more conservative over the years.)

This map seems to show that statistically, Greens support is fairly widespread across the Division. There is also a lot of detail left out: for example, many votes were cast at pre-polling Centres, and the numbers are large enough to significantly affect the result. This table compares votes cast in the Division on the day, which is what the map shows, against votes cast at the pre-polling centres:

Clearly first preferences show the Greens votes exceed votes both for the Labor and Liberal parties on the day. At pre-polling, Labor did better than the Greens. It does seem though that the Liberal first preferences were very much smaller, so it seems a bit paradoxical that the Greens were knocked out first, giving a final TCP of Labor and Liberal. But that's preferences for you!

The win

The current leader of the Australian Greens is Adam Bandt, who is the Federal MP for the Division of Melbourne. He has held this seat, increasing his majority at each election, since first winning it in 2010.

The next map shows the TCP results from the most recent election, which shows that Bandt has a TCP majority at every polling place except two:

As with all such maps, the amount of information here is not huge - but it looks nice. In particular, it shows that statistically, Greens support is fairly widespread across the Division.

Other similar informational sites

There are other sites, showing results at various booths. One is the excellently named PollBludger from the political analyst Willian Bowe, who is described on the site as "is a Perth-based election analyst and occasional teacher of political science. His blog, The Poll Bludger, has existed in one form or another since 2004, and is one of the most heavily trafficked websites on Australian politics."

Another site is The Tally Room from Ben Raue, who has an adjunct appointment at the University of Sydney. A very nice addition to this site is a tutorial on how to create your own maps, in this case using Google Earth. (I don't know how recent this is, though.)

(The above site is not to be confused with the AEC's own Tallyroom which also has a lot of results for the downloading.)

However, I don't know of any sites which add Voronoi diagrams around the polling booths so as to give a picture of the voting characteristics of an electorate. Whether this is of any use is of course a moot point.