In 1861, the Otago Provincial Council decided to commission a geological survey in the hope of finding minerals - especially gold - and hired Edinburgh-born geologist James Hector for the job.
Between 1862 and 1864, he explored and mapped all of Otago province and Southland.
He became a dominant 19th century science figure in New Zealand and geologists celebrate his birthday, March 16, as Hector's Day.
The Hocken Library marked yesterday's milestone by unveiling a restored copy of one of Hector's 1860s geological maps of Otago.
The map once hung in the University of Otago's geology museum before deterioration prompted a move in the 1970s to have it restored.
Hocken Library librarian Sharon Dell said the 1.5m wide map was sent to the Auckland Art Gallery for conservation.
However, it became overlooked and was forgotten for about 25 years.
"It was not until they were getting ready to move out of the building that they investigated this roll of paper, and there it was," she said.
In 2007, it was returned to the Hocken and a "generous" grant from the University of the Third Age Charitable Trust enabled it to be fully conserved and digitised.
A website was also created, allowing the map to be seen around the world, with a history written by geologist and author Simon Nathan.
A scaled-down copy of the map was given to the geology department at an event last night, with the original preserved in the Hocken's map collection.
"I think the geology department are really thrilled," Ms Dell said.
University of Otago professor of geology Ewan Fordyce calls it "the map that changed the South".
"Hector was quite a pivotal figure in New Zealand geology ... [the map is] an important part of Southern science," he said.
Looking at the original "really takes you back to the time when the person was standing there actually executing it".
However, he knew it was "too delicate to have on public display" and was looking forward to having the "excellent" digital copy at the geology department.
Visit www.library.otago.ac.nz/hocken/hector/map.php to learn more and to see a copy of the map.
