In 1931, the town of Rugby, North Dakota, erected a 15-foot stone monument declaring itself the "geographical centre of north America."
For 85 years, the town has enjoyed a steady stream of tourists to the monument and local gift shops.
But recently, Rugby received an unwelcome challenge, from a bar about 100 miles south.
"By our calculations, the centre of North America is in Robinson, a couple feet outside Hanson's Bar," said Bill Bender, the owner of Hanson's and mayor of Robinson, North Dakota.
“We have as much claim to it as anybody does.” Last summer, Mr Bender registered Hanson’s Bar as the owner of the phrase “geographical centre of north America” with the US Patent and Trademark Office.
Rugby’s registration had expired in 2009, when the town failed to file a renewal.
Now the science of geography may prove them both wrong.
When Peter Rogerson, a geography professor at the University at Buffalo, heard about the kerfuffle, he decided to weigh in.
In 2015, he had published a new method for calculating geographic centres. Using this method, he found that the continental centre was in a town called (wait for it) Center, North Dakota.
By car, Center is 233kms southwest of Rugby and 144 kms west of Robinson.
The novelty of Mr Rogerson’s method is the map projection he used.
Map projections transform Earth’s three-dimensional surface into two dimensions. The process always introduces some distortion, in shape, area, distance or direction.
Perhaps the most well-known projection is the Mercator, which greatly distorts size, showing Greenland at roughly the same size as Africa.
To calculate geographic centres, Rogerson uses the azimuthal equidistant projection, which accurately shows distances and angles from its center, at the expense of shape and size toward its edges.
With accurate distances, Mr Rogerson can calculate the point at which the sum of squared distances to all other points in the region would be smallest ? the mathematical definition of a geographic centre.
“When I ran my computer program and looked at the final latitude and longitude, I was astounded to see that it was in a place called Center,” he said of calculating the midpoint of North America.
New York Times