It has just 78 inhabitants but will officially become the geographical heart of the European union after Britain leaves

When Karin Keßler harvested her winter oilseed rape last summer, she was vexed by the sudden slump in the market price and put the crop into storage to wait for its value to rise.

“The Brexit referendum had rattled the markets,” Keßler, the 51-year old farmer recalled. “I ended up selling in December instead.”

In the run-up to this year’s harvest in mid-July, her main concern will be quite different: how to manoeuvre her combine harvester around the wooden post in the field marking the future geographical centre of the European Union.

“It was a bit of a surprise to wake up to the news,” Keßler said. “You could say Brexit has rattled us again, but in a good way, if that’s possible.”

Facebook Twitter Pinterest From left: Jürgen Götz, the mayor of Gadheim, Karin Keßler, and Walter Dieck, the village spokesman. Photograph: Kate Connolly/The Guardian

Keßler was in the village shop in Gadheim – home to just 78 souls – last Wednesday when she was told the news by the baker, who had herself just heard it on the radio: the hamlet she had grown up in and where her family has farmed for 150 years will officially become the geographical heart of the EU after Britain leaves.

The ruling, which filtered through to Gadheim on the day that Theresa May triggered article 50 and started the process of quitting the bloc, has come from French cartographers at the geographic information engineering institute (IGN) in Paris.

They have decreed that the EU’s eastward shift following Britain’s exit will mean the village of Westerngrund, about 50 miles (80km) away, relinquishes the title to Gadheim, just north of Würzburg in Bavaria.

The precise coordinates are 9º 54’ 07” E and 49º 50’ 35” N. It was not until Keßler’s 25-year-old son, Michael, a software engineer, put them into his mobile phone that she realised the location was not only in Gadheim, but right in the middle of her 55-hectare farm, placing it as she put it, “at the belly button of the EU”.

Bernard Bèzes, of the IGN, said the calculation had been made after people contacted the institute following the EU referendum “asking to know precise measurements for the centre of a post-Brexit EU”.

The calculation, he explained, was made by digitally flattening out the entire EU terrain, then in effect lifting it up like a piece of cloth to find its precise middle.

His institute has also calculated the centre of the continent of Europe to be in Lithuania, much to the delight of the village of Purnuškės. .

Brigitte Heim was happy to explain why being the centre of the EU matters so much. She is the mayor of Westerngrund, which became the new centre after Croatia joined the club in 2013 and kept the crown a year later when the French island group of Mayotte in the Indian Ocean joined, moving the centre 500 metres east.

Facebook Twitter Pinterest Gadheim considers itself to be a Brexit winner. Photograph: Kate Connolly/The Guardian

“We have about 10,000 visitors who come here every year just because of this,” Heim said. The village has marked the spot, on a field on the edge of the village, with an EU flag and some picnic tables. The official inauguration of the spot was accompanied by a brass band. A hiking route between Westerngrund and the village of Gelnhausen Meerholz – the title-holder from 2007 after Romania and Bulgaria joined – was also instigated.

Heim said she had no hard feelings towards Gadheim for stealing Westerngrund’s thunder. “We always knew it was a gift lent to us for a limited amount of time,” she said. “We just set about making the most of it. But we’re shocked and saddened by Brexit. When we earned the title it was because a country had joined, now we’re losing it because for the first time a country is leaving the EU – we just hope the negotiations might take a little longer than two years so we can hang on to it a little longer.”

Facebook Twitter Pinterest A stone column marks the geographic centre of the European Union. Photograph: Alamy Stock Photo

In the 1950s when the EU was still a small community of six, the centre was located close to the Franco-Swiss border just outside the city of Besançon. By 1987, with 12 members, it had shifted to the central French village of Puy de Dôme and in 2004 to Germany, where it has been ever since.

Kurt Adelmann said he was mystified as to why anyone would want to leave the EU. Adelmann, 81, a retired telecommunications technician, drove from his home in nearby Veitshöchheim and along the dirt track at the foot of the Franconian hills to photograph the spot for himself when the news reached him.

“I was a nine-year-old boy when war ended,” he said. “But I remember all the bombing raids in and around this area, and being haunted by the grave of a German soldier in the woods where we played. I can appreciate the fact we’ve enjoyed 70 years of peace and the EU, I think, has been the best way of guaranteeing that.

“Still, I can’t say it’s not nice that we’re being put on the map. If there’s a Brexit winner, then maybe it’s Gadheim.”

Jürgen Götz, the mayor with responsibility for Gadheim, said he hoped the news would encourage more investment and tourism to the area, whichboasts one of the finest rococo gardens in Germany and a medieval pilgrimage site.

“Of course we have mixed feelings about all this,” he said, standing by an EU flag that has been hoisted in the centre of the village. “We’re still discussing what we’ll do: put up a proper flag pole, erect a sausage kiosk, a hiking route with Westerngrund, that sort of thing. But we’ll enjoy it while it lasts. We can also wish that the talks might collapse and it’ll never happen. Then again, if Scotland or Serbia were to join, everything will shift once more.”