North versus south in Batman All the green dots south of Bell Street? They are polling booths won by the Greens. The red to the north are Labor-won booths. The man who made the map for his blog, University of Melbourne academic Michael McCarthy - a professor of biosciences by the way, not a political scientist or urban geographer - says: "You can see the really massive north-south divide. The further south from Bell Street you go, the lower the ALP vote is and the higher for the Greens. North of Bell Street is the opposite. Bell Street is where it turns." The Greens picked up plenty of votes in the electorates of Wills and Batman. Credit:Justin McManus On Twitter, which loves this stuff, the jokes flowed when Professor McCarthy first posted his blog. Bell Street was the 'Tofu Curtain.' The 'Great Wall of Quinoa.' 'The Corduroy Line.' "My wife came up with the best one," he says. "The Hipster-Proof Fence."

Certainly in real estate, properties south of Bell Street are marketed as such, and they cost significantly more on account of proximity to Northcote, Brunswick, Brunswick East and Thornbury, more public transport and more bike tracks. Dr Elizabeth Taylor from the Centre for Urban Research at RMIT says south of Bell Street should take the New York style acronym of SOBS. Certainly some of the house prices for cramped blocks SOBS are enough to make an inner-urban educated cyclist weep. "If a property is north of Bell Street the real estate agents will say it is 'not far' from Bell Street," Dr Taylor says. "People who buy to the south can tend to have status in mind." And they love The Greens. We now have the proof. According to the party's state director Larissa Brown there are several reasons for the huge green vote south of the great divide. Most of the party's 600 volunteers in Batman - The Green Army - live in Brunswick, Thornbury and Northcote.

The Green Army started its campaign of doorknocking for this election in the south, and moved north.

The party had identified growing clusters of potential Greens voters in the more densely populated SOBS. Ms Brown said despite the stark divide shown on the map the Greens still had big swings to them in almost all polling booths north of Bell Street, especially in Reservoir, where party strategists have learned that Greens voters have moved in but only if their house is close to public transport or creeks. "So we would expect any other booths in the north near creeks and trains to keep climbing for us. We will probably doorknock harder in those places in the future."

In the neighbouring seat of Wills, bordered from Batman by the Merri Creek, it's a similar story. Slightly less stark, but similar. It shows a green march north, but also more red presence to the south. North versus south in Wills ​ So what does this all mean? Gentrification. The same old story. Younger, wealthier people who are university-educated and work in well-paid professions are continuing their march north. It started in Fitzroy many moons ago, then north through North Fitzroy, Clifton Hill, Northcote then Brunswick and Thornbury and now into Coburg, Preston, Reservoir and beyond. It is now affecting voting patterns with the Greens on the rise and the Liberal coalition on the slide. Political experts forecast that electoratal boundaries in the inner-north could well be shifted soon to reflect changing demographics.

In the 2011 census, Thornbury West - which is SOBS - had 39 per cent of residents with university qualifications. Dr Taylor expect's this year's census to show an increase in the same area to more than half. The local 'amenity' south of Bell is seen to be better, with the neighbourhoods to the north built post-war, with less strip shopping and more reliance on cars. Median house prices are sitting at around $1million in Northcote this month, and about $650,000 in Reservoir.