Peru: 300 new Nazca images discovered with AI help

It took nearly a century to discover the 403 figurative geoglyphs that became known as the Nazca Lines. Thanks to the use of AI, researchers have now managed to nearly double the number of scratch images in a short time, scientists report in the Proceedings of the National Academy of Sciences (PNAS).

Even with limited training samples, the AI ​​proved effective at detecting smaller relief-like geoglyphs, which are very difficult to detect in contrast to the giant line-like scratches in the Peruvian highlands, the researchers said.

Aerial photographs evaluated using AI
For their research, Masato Sakai of Yamagata University in Japan and his colleagues used an AI system adapted to the analysis of aerial photographs. They trained it to recognize the typical lines in the desert floor using parts of known Nazca geoglyphs. The search focused on the smaller Nazca geoglyphs of the so-called relief type, which are on average only about ten meters high.

Of the 1,300 geoglyph candidates identified using AI, the researchers have already examined several in situ and discovered a whopping 303 figurative relief images. Based on the results so far, they expect to find many more – more than 200 – more.

Distribution of scratch images analyzed
The improved representation of the figurative geoglyphs allows us to analyze the motifs and their distribution in the Nazca pampas, the researchers report. Using AI, it was discovered that relief-type scratch images predominantly (in 81.6 percent of cases) depict human subjects or things modified by humans, such as domesticated animals and decapitated heads.

They are usually within sight (an average of 43 meters away) of ancient trails crisscrossing the Nazca pampas and were likely built and surveyed by individuals or small groups, the scientists led by Masato Sakai report.

The giant, linear crab statues, on the other hand, are said to feature mostly (64 percent of the time) wild animals. They are located an average of 34 meters from the extensive linear/trapezoidal geoglyph network, suggesting they were likely built at a community level and used for ritual activities, the researchers said.

Usually only visible from a great distance
The Paracus and Nazca cultures are considered the founders of the lines. The scratch images were made between 500 and 500 AD. Due to their enormous size, they can only be seen from great distances, from the surrounding hills or from airplanes.