History of triangulation – origin of the method The method of surveying by triangulation was first introduced by the Dutch mathematician Willebrord Snell (Snellius) in which year?

Introduction / Context:
Triangulation revolutionized large-area surveying by allowing positions to be determined from a network of triangles measured with a few base lines and many angles. Knowing the origin of the method helps place modern geodesy and national mapping in historical perspective.

Given Data / Assumptions:

• Attribution is to Willebrord Snell (Snellius), a Dutch mathematician and astronomer.
• Question asks for the specific year commonly cited for the introduction/publication of the method.

Concept / Approach:

Snell’s work “Eratosthenes Batavus,” published in the early 17th century, outlined methods that underpin triangulation-based distance determinations and mapping. The year widely associated with his formal introduction of triangulation techniques into surveying practice is 1615. This predates the widespread adoption of triangulation for national surveys in later centuries (for example, Cassini in France, the Principal Triangulation of Great Britain, and the Great Trigonometrical Survey of India).

Step-by-Step Solution:

Verification / Alternative check:

Standard histories of geodesy and surveying list 1615 as the key date for Snell’s triangulation work, aligning with academic references and encyclopaedia entries.

Why Other Options Are Wrong:

Dates like 1600, 1630, 1650, 1680 either precede the published work or belong to later applications by other surveyors; they are not the canonical introduction date.

Common Pitfalls:

Confusing Snell’s triangulation with later network refinements; mixing the date with other Dutch contributions in cartography.

Final Answer:

1615