The question of how archaeologists know where to dig to find features and artifacts is one that many people are curious about. There are a few incredibly interesting ways that archaeologists decide where to put a shovel in the ground.
Reading is fundamental
Written accounts and maps
Over the history of humans walking the earth, when people chronicled their lives and history, clues to ancient sites can be found. Archaeologists and researchers consult old documents, records and maps for clues. For example, Norse sagas gave archaeologists the idea that there might be Viking sites in North America. And when archaeologists decided to search the area where Greyfriars Church was believed to be in Leicester, the skeleton of Richard III was found under a car park. Even legends like the Epic of Gilgamesh have been found to reference actual places. Some historians believe artifacts found belonged to Gilgamesh who was believed to be a king from the Iraqi city of Uruk.
Sign langage
Surveying
Whether due to research or luck, there are areas that archaeologists know where to look. In places like England and Ireland, large mounds in the landscape are known to house burial sites, with Sutton Hoo and Knowth being two of the most famous examples.
Systematic surveys are the archaeologists tried and true method to uncover artifacts and sites. By walking the landscape and looking for artifacts peeking out of the dirt or other signs of habitation, archaeologists have uncovered some truly astounding discoveries. In a well-documented survey on the island of Cyprus in the 1990’s researchers recorded about 9,000 artifacts from as far back as 3,000 BCE, a sure sign that the location was home to a site that was occupied in ancient times.
Oops, there it is
Farmers and Construction workers
Oftentimes archaeologists hear about a site after someone stumbles across an artifact. A farmer plowing up a field or construction and roadcrews come across something unexpected during their work. In 1974, farmers digging for a well in Xi’an, China found what became called the terracotta army, dating from 210-209 BCE. And in another amazing discovery that decade, in 1978, electrical workers in Mexico City found something on the job that led to the discovery of the Great Temple of the Aztec Empire.
Bird's eye views
Planes and drones
Getting a view from above is another way archaeologists know where to dig. Flying overhead by plane or using drones allows researchers to see features that might not be easily accessible or viewable on foot. And more recent technologies that allow views from satellite and space—like Google Earth—have turned up numerous sites in recent years. A tenacious teen in Canada helped pinpoint the location of an ancient Mayan city by reading ancient books and matching ancient star maps to satellite imagery. And, a treasure trove of hundreds of previously unknown Nazca Lines figures in Peru were discovered using drones.
How low can you go?
Ground penetrating radar and LiDar
A tool that researchers use if they have a hunch that something is beneath their feet is ground penetrating radar. It allows a view of up to 100-feet below the surface. To see this in action, this video explains how a team used ground penetrating radar to find the site of a Revolutionary War battle.
Another incredible tool uses light detection with LiDar to produce images in three dimensions. LiDar pulses have helped reveal previously unseen archaeological features that hide under things like thick vegetation. One notable site was found in Cambodia at Mahendraparvata an early city of the Khmer Empire.
Interested in learning more? Check out the Archaeological Institute of America or go on an archaeological dig and learn while doing.