1 Introduction
Providing consistent, reliable mapping for the nation is a role that jurisdictions worldwide have found to be necessary for a number of core purposes such as planning, property valuation and national defence. National mapping organisations (NMOs) have played a vital part in enabling these functions. However, we are in the throes of an information revolution in which geography and geographic information (GI) are assuming greater relevance in a much wider context. GI is moving to the mainstream. This paper illustrates Ordnance Survey’s activities today with respect to these developments.

2 A brief history
Ordnance Survey was established as a military organisation in 1791 at a time of great turbulence in Europe. Fearing a French invasion led by Napoleon, the British Government instructed that a map of the south coast be drawn up. The first map depicting Kent, the most vulnerable county to invasion, is shown in Figure 1 below. This momentous decision led to the establishment of Ordnance Survey and the subsequent mapping of the whole of Great Britain (the countries of England, Wales and Scotland within the United Kingdom).


Figure 1: Extract from the first Ordnance Survey map of Kent, finalised in 1801
Ordnance Survey continued to maintain and develop topographic mapping of Great Britain throughout the nineteenth century. By 1895 a national set of mapping at 25 inches to the mile was completed and a new metric National Grid was introduced following retriangulation in 1938.

In 1971 Ordnance Survey embarked upon a revolutionary new programme of digitising all 230,000 of its large-scale paper map sheets. The primary objective in undertaking this was to improve internal map production efficiency (Figure 2); the widespread use of GI that we see today was unthinkable at the time. By 1995, nearly a quarter of a century later, this immense programme of work was completed and Ordnance Survey had enabled Great Britain to become the first country in the world to truly enter the digital era.

Figure 2: One of the earliest plots from a digitised 1:2500 digital map, 1974