WILLIAM SMITH FROM FULLERS EARTH TO GOOGLE EARTH

William Smith's maps have been studied in detail by many researchers interested in Smith's place in the history of geology but few have looked at the maps in the context of modern geological information. The author has been interested in Smith's maps for the past decade and during that time has digitised a number of his maps and incorporated them into a Geographic Information System (GIS).

A major problem in transforming Smith’s maps into a GIS is that there is no indication of the projection used on his maps. There are marginal graticules showing latitude and longitude, but no internal lines and although the coastline is recognisable, it does contain positional errors. However, Smith was fortunate to have the talented John Cary as his map maker. Cary's local surveying of town and village positions was excellent and he used much of this information on the elegant base map he produced for Smith's 1815 map.

In order to discover the projection used, a series of iterative tests were undertaken on the map graticules using projections in common use during the early 19th century. Overall the best fit was the Cassini projection. Using this projection, the Smith maps were georeferenced to real world coordinates based on the positions of Cary's towns and villages.

The base map prepared by Cary for the 1815 map essentially predates the 1st Principal Triangulation. However, some of the Smith-Cary county maps were concurrent with early phases of the triangulation and in several cases include information derived from the triangulation.

Once in real world coordinates, Smith's maps can be compared with modern geological mapping. This comparison shows that for much of the Cainozoic and Mesozoic of England Smith's mapping was remarkably good. Modern technology makes it possible to drape Smith's maps on a digital terrain model and view them in 3D. These visualisations dramatically illustrate Smith's complete understanding of the principles of stratigraphy.

Smith's wonderful panoramic cross-sections have been located on his maps as have fossils from his Strata Identified publication.

These studies have been incorporated into a new website, William Smith's Maps-Interactive. This is a free educational resource which can be found at http://www.strata-smith.com