John Playfair was a leading figure in the Scottish Enlightenment, professor of mathematics and of natural philosophy at Edinburgh University and, as the driving force behind the iconic observatory on Calton Hill, he helped establish the city as the "Athens of the North".
Playfair also brought his orphaned six-year-old nephew, William Henry Playfair, to Edinburgh in 1794, and oversaw his development in to one of the most influential Scottish architects of the 1800s. He was a wealthy man when he died in July 1819, but he was buried in an unmarked grave in Old Calton Cemetery, on Waterloo Place.
An impressive monument to Playfair, designed by his nephew William, stands on Calton Hill. But only now, 191 years after he died, will a 1000 granite memorial finally mark his grave.
Cliff Porteous, a retired geologist who leads parties over Calton Hill, and started a campaign to mark the grave, said: "As a geologist, John Playfair is a hero of mine, particularly for his (1802 book] Illustrations of the Huttonian Theory of the Earth.
"I take people over Calton Hill to the monument built by his nephew William but when a tourist asked to be taken to his grave I could not locate it.
"I tracked it down to the Old Calton burial ground, where his name is listed on a notice board at the entrance. Eventually, after days of research, it was confirmed that John Playfair was buried in an unmarked grave adjacent to the philosopher David Hume's monument.
"The lair has three walls with a small step, all open to the heavens, but nothing to tell people that this remarkable figure in Scotland's and Edinburgh's history - an important mathematician, astrologer, philosopher and geologist - is buried there. John Playfair has an impressive monument on Calton Hill, but he has lain in an unmarked grave for 191 years.
"I'm pleased to say that this state of affairs will be rectified with a suitable granite plaque," Mr Porteous added.
Conservation body Edinburgh World Heritage will help fund the project "in recognition of Playfair's contribution to the city". A spokesman said: "John Playfair is a leading figure associated with the Scottish Enlightenment, along with the likes of David Hume and Adam Smith.
"It is important that his grave should be commemorated in this way."