Ghost miles: How did 49km go missing from Bluff to Cape Rēinga?

How do so many expert agencies come up with different distances between two of the most recognised and photographed signposts in New Zealand? Craig Hoyle investigates.

Somewhere, somehow, 49 kilometres have gone missing in Aotearoa. Government agencies don’t know where they are. Neither do a range of local boards, experts and transport policy wonks.

But what we do know is this: at opposite ends of the motu, in Bluff and Cape Re¯ inga, two iconic road signs give very different numbers for how far it is from one end of the country to the other.

This mystery came to my attention a few weeks ago.

I’d been in Invercargill for a week – I grew up in the deep south – and popped out to Stirling Point in Bluff for old times’ sake. Many a childhood Saturday was spent around that sign, fish and chips in hand, as biting southerlies blew from Antarctica.

I snapped a pic of the sign: 1403km to Cape Rēinga.

The next weekend, having zipped the length of the country, I was in Cape Rēinga with a friend who was visiting from the UK. This was, I enthused, the perfect chance to get a matching set of pictures.

I lined up my shot beside the lighthouse, zoomed in, and… wait a minute: 1452km to Bluff.

Something clearly did not add up. ‘‘Might be time for an investigation,’’ I wrote on Facebook.

A few weeks later I’m on the phone to Ray Fife, who chairs the Bluff Community Board. He’s as confused as I am.

‘‘It’s strange that one sign says one thing, and the other says another. You’d think it’d be the same at each end!’’

Fife doesn’t know who’s responsible for setting the distances on the signs, but has some helpful suggestions for who to call next.

My next stop is the NZ Transport Agency. ‘‘This is a bit of an odd one, but I’m wondering if Waka Kotahi is able to provide an official driving distance between Bluff and Cape Re¯ inga,’’ I email.

Media manager Megan Heffield comes back with a reply that is both helpful, and deepens the mystery.

‘‘The distance by road, according to Google Maps, is approximately

2067km, including the ferry crossing. If you take out the ferry crossing, I get approx. 1975km.’’

Heffield adds that the road signs both appear to be referencing ‘‘the distance as the crow flies’’.

This leads me down a rabbit hole about whether crows fly over open ocean, given the direct route from Bluff to Cape Rēinga runs hundreds of miles offshore from the west coast.

I then discover there are no crows in Aotearoa, and the ocean-flying question becomes moot.

So just how far is it from Bluff to Cape Rēinga, as the albatross flies?

It’s time to call on Toitū Te Whenua, Land Information New Zealand (LINZ), which records Aotearoa’s physical features ‘‘to provide up-to-date maps and information’’.

Here at last, we have answers. ‘‘The point-to-point distance between the signposts at Bluff and Cape Rēinga is 1401km,’’ says LINZ communications manager Steve Janes.

‘‘Note that this does not include variables from things like the road network, topography etc.’’

So there we have it: the Bluff sign, saying 1403km, is much closer to being correct.

Janes adds there are several ways to calculate distances, ‘‘and different methods will give

slightly different results’’ – which may be why the Bluff sign is 2km off.

‘‘For the figure above, we have calculated the distance using the ellipsoidal model of the Earth, which is used for the New Zealand Geodetic Datum 2000 (the country’s official datum).’’

The only thing left to find out is why the Cape Rēinga sign is so… well, wrong.

The trail leads from Far North District Council to local iwi, who recently oversaw an upgrade of facilities at Cape Rēinga – although apparently they’re not responsible for the iconic sign.

The Department of Conservation (DOC) is my final stop. Here, finally, are answers from senior ranger Laree Furniss.

‘‘We are aware of the discrepancy and will be looking to change the distance on the Cape Rēinga sign when the sign is next due for upgrading/replacement.’’

So does DOC have a timeline for upgrading the sign?

‘‘No sorry, it’s not in the immediate plans though.’’ Mystery solved.

I let Ray Fife know that the Bluff sign, while still a couple of kilometres off, is much closer to being correct.

‘‘Great news. Thanks Craig.’’ Meanwhile the Cape Re¯inga sign will likely be wrong for a few more years yet, meaning any albatross making the journey may unexpectedly have half an hour spare.

CRAIG HOYLE, JOHN HAWKINS, BROOK SABIN / STUFF Bluff Community Board chair Ray Fife, above, is as confused as everyone else at the discrepancy between the distances on the Stirling Point, inset left, and Cape Re¯inga, above, signs.