UCL in the News: Design of London's amphitheatre revealed

While it was clear that the structure was roughly oval, like other examples, the precise geometry employed was less apparent.

"How were the arena walls set out on the ground by the Roman engineers?", Dr Marek Ziebart [UCL Civil, Environmental & Geomatic Engineering] and his colleagues ask in the Journal of Archaeological Science. "Did the geometrical pattern of these walls conform to an elliptical shape, to a set of interlocking ellipses, or to some other pattern?" …

Dr Ziebart's team tested the proposition that an ellipse was employed in the case of the London arena by applying a set of complex mathematical algorithms to create a theoretical model of an ideal ellipse that could be tested against on-the-ground data. …

One surprising conclusion was that around the entry there was an "embrasure" where the arena walls were pulled back slightly, departing from a pure ellipse by a short distance; another was that "the fit of the single elliptical curve to the data outperforms the fit at Sarmizegetusa, a strong indication that the ellipse models successfully the original geometric form of the curve", although not conclusive proof, since an eight-arc oval could also be fitted to the data. …

Norman Hammond, 'The Times'