Page "Triangulation" Paragraph 21

On land, the Dutch cartographer Gemma Frisius proposed using triangulation to accurately position far-away places for map-making in his 1533 pamphlet Libellus de Locorum describendorum ratione ( Booklet concerning a way of describing places ), which he bound in as an appendix in a new edition of Peter Apian's best-selling 1524 Cosmographica.

This became very influential, and the technique spread across Germany, Austria and the Netherlands.

The astronomer Tycho Brahe applied the method in Scandinavia, completing a detailed triangulation in 1579 of the island of Hven, where his observatory was based, with reference to key landmarks on both sides of the Øresund, producing an estate plan of the island in 1584.

In England Frisius's method was included in the growing number of books on surveying which appeared from the middle of the century onwards, including William Cunningham's Cosmographical Glasse ( 1559 ), Valentine Leigh's Treatise of Measuring All Kinds of Lands ( 1562 ), William Bourne's Rules of Navigation ( 1571 ), Thomas Digges's Geometrical Practise named Pantometria ( 1571 ), and John Norden's Surveyor's Dialogue ( 1607 ).

It has been suggested that Christopher Saxton may have used rough-and-ready triangulation to place features in his county maps of the 1570s ; but others suppose that, having obtained rough bearings to features from key vantage points, he may have estimated the distances to them simply by guesswork.