Professor Karim Sadr led a team of scientists to excavate the area, before using the specialist technology to map out satellite images of the lost city – known as Kweneng. The machine then sent out a laser beam, hitting any objects in its way, before reflecting back. The results revealed a 200-year-old stretch of land around 30 miles south of Johannesburg that scientists believe may have once housed up to 20,000 citizens.
Dr Sadr revealed how his team exploited the same technology used to uncover ancient Mayan cities.
Speaking in March 2018, he said: “This technology, called LiDAR, was used to ‘redraw’ the remains of the city, along with the lower western slopes of the Suikerbosrand hills near Johannesburg.
“Four or five decades ago, several ancient Tswana ruins in and around the Suikerbosrand hills, about 60km south of Johannesburg, had been excavated by archaeologists from the University of the Witwatersrand.
“But from ground level, and on aerial photos, the full extent of this settlement could not be appreciated because vegetation hides many of the ruins.
“LiDAR, which uses laser light, allowed my students and I to create images of the landscape and virtually strip away the vegetation.
“This permits unimpeded aerial views of the ancient buildings and monuments.”
LiDAR stands for “Light Detection and Ranging,” and it is the primary sensor used in car systems, but has also been vital in recent years for rediscovering lost civilisations.
Dr Sadr added: “It uses billions and billions of pulses of laser lights, something like four or five hundred per square metre.
“As soon as each pulse hits an object – any solid object, a bird or a leaf or a tree or the ground – it reflects straight back to the machine and then the machine can figure out where that interception took place in three dimensions.
“So once the plane collects all of this data, masses of it, and it comes down to the ground, we can project it.”
The team originally gave the codename SKBR to the site they uncovered, but it was quickly renamed Kweneng.