Map of a Nation, By Rachel Hewitt

Nowadays Ordnance Survey maps are lovingly protected in plastic folders and hung around the necks of right-to-roamers. But as this scholarly cartographical history points out, the seeds of the OS map are largely military in origin.

Following the 1745 Jacobite Uprising it became clear to the crown that the Highlands were a largely unmapped wilderness of fell and bog.

To the rescue came William Roy, who, handy with an astrolabe, devoted himself to translating this terra icognita onto the page.

In this lively overview, Hewitt explains how over the course of the next century developments in scientific thinking, technological advances and a critical dose of Anglo-French collaboration eventually led to the creation of the OS's First Series in 1870.