Some aspects of Roman land surveying are documented in the Corpus Agrimensorum and other surviving Latin texts and map fragments. The texts describe the process of creation of divided land, so-called centuriation, more or less complete examples of which may still be seen on the ground. Their study makes it increasingly clear that the underlying surveys were not only the basis for land division but also a planning framework for military structures, including roads.

In 1990 the hypothetical existence of one of these surveys was proposed in Essex, and at that time it seemed possible that a visible part of a Roman road, Margary 300 near Radwinter, could have been designed to join opposite corners of its squares. The question was whether or not this 1:1 relationship could predict the course of the road nearer to Great Chesterford, where its position was no longer clear. Three hypothetical projected routes had already been proposed, but none of them maintained the 1:1 relationship. However, by ignoring them and looking closely on the projected 1:1 line, it was possible to see, on Google Earth and Bing images, parallel dark features near Great Chesterford separated by 12m and conforming accurately to the 1:1 relationship. These seem likely to be traces of the road’s side ditches and if so, demonstrate the usefulness of the land survey hypothesis, when compared to the invalid assumptions underlying the earlier reconstructions.

Further study of the known Roman roads meeting at Radwinter reveals that they are symmetrically arranged about the single point at which they seem to be aiming. This may be for both aesthetic and practical reasons. A geophysical survey is currently planned in the field containing this point, where the presence of a Roman settlement has already been suggested. At Great Chesterford the roads to the early fort may also be studied further. The trigonometrical relationship (or lack of relationship) of the hypothetical land survey to these and other Roman structures may allow relative dates to be suggested.

How was the course of a Roman road in Essex predicted by a land survey hypothesis?