Tagged with Transport

Why map data sometimes matters

I was contacted recently by a parent campaigning for a local school to ensure its admissions policy is properly applied. Over-subscribed schools like this one are a common source of frustration and worry up and down the country.

Here’s the rub. Which of these two homes would you say is closer to the school, and therefore more likely to secure a place?  By the way, I’m not sure that the location on the left actually is within the catchment area, it’s just a place I randomly chose to illustrate the coming point…

Routes to the school from two locations using CloudMade maps, the home on the right wins by 500m.

Parents at the location on the right were told they were too far from the school. The method they use to calculate safe distances to the school actually suggests that the location on the right is farther away than the location on the left!

Why?

Because they are calculating distances using a model that measures the distance as if you are driving a car. If you try that, you get a totally different result:

Routes plotted for cars to get to the school, the home on the left wins by 400m.

The school’s model uses the Ordnance Survey ITN maps, and apparently doesn’t account for this short footpath at the end of one road. It was pedestrianised 25 years ago.

Happily OpenStreetMap has all the relevant data (and a few minor corrections the parent, Jasia, pointed out to me) so anybody can plot the route to prove the point.

Incidentally, if you fancy showing your support for this campaign download this letter to the governors, sign it and send it to the address at the top of the document.

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Boris scuppers the South London Line

One of the London Mayor’s favourite tactics is to totally confuse an issue, joking around to avoid anything sticking. With an issue like the South London Line he’s in his element. Except that residents of south London might prefer if he used his wit to help save public transport services, rather than trying to deny any responsibility.

Jenny Jones and me by a SLL train

To recap very quickly, the excellent train service (which I use daily) is due to be axed in 2012. Boris has tried to claim it’s the government’s responsibility; that it is purely a technical decision which he can’t reverse; and that he is fighting our corner (only when his hand is forced, of course). In fact, we can be pretty sure that it all comes down to money, and that Boris won’t stump up the measly £2.4m per year for two years out of a massive central Government grant to save the line because he came up short on the East London Line extension.

OK, this is getting a bit nerdy. But today Southwark Councillor and London Assembly Member Jenny Jones stuck it to him again, asking if he would set-up a meeting between Transport for London and Network Rail to discuss the technical issues with London Bridge station. His answer? No.

He can fluster and wheeze about his commitment to public transport all he likes, but campaigners in south London know a Mayor who doesn’t give two f**cks about our services when we see one!

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