Monuments in America take many forms – faces carved in a mountain, bronze statues overlooking a harbor – but in Southwest Nigeria, one monument spanning centuries is at the center of the largest collection of LiDAR data in history. Sungbo’s Eredo in Nigeria is a system of walls and ditches that is considered the largest earthen enclosure in the world. Using LiDAR, or “light detection and ranging” technology, a team of researchers from William & Mary just completed its work to measure the monument, collecting data over a five-year period.
Led by William & Mary Associate History Professor Gérard Chouin, the LiDAR project was the result of interdisciplinary work across the university, involving the history and anthropology departments and the Center for Geospatial Analysis.
“We have a state of conservation of the monument that can be used in the decades to come to measure and assess progress (and) destruction of the monument,” Chouin said.
According to Chouin, the scale of the project dwarfs all other projects in heritage studies conducted in Africa. One thousand square kilometers of data were collected, 30 times the total area of land previously documented with LiDAR, a system of measurement that uses light in the form of pulsed lasers to map out three-dimensional spaces.
In all, the monument has a total length estimated around 170 kilometers.
“William & Mary very much encourages cross-disciplinary research,” said Neil Norman, associate professor of anthropology. “Collaboration has allowed for Nigerian students, undergraduate and graduate students to be a part of the research progress in many different ways.”
Data is one of the core initiatives of W&M’s Vision 2026 strategic plan, which seeks to integrate computational thinking and data fluency across all fields of research.
Foundations of the eredo earthen enclosure
The name Sungbo’s Eredo contains its own history. Eredo is the Yoruba word for a ditch or a bank, and Sungbo comes from the name of the woman who is said to have used her immense wealth to fund labor for the ditch.
The eredo is not merely a piece of land, but provides various functions for the communities it surrounds. As Chouin explained, as a result of the city-state Ijebu that was created in the late 14th century and existed until the 19th century, a trench system was created within the ditch as a line of defense. What at first look like walls are actually build-ups of dirt from the banks.
Additionally, the eredo is theorized to have been created as an act of prestige, with its vastness and depth a boast of the capacity to accumulate people for extreme labor.
“The idea would be that the political power of the architect was basically proving through that monument that they had access to labor,” Chouin said. “It was rich in people.”
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