Rankine's method

Rankine's method is a technique for laying out circular curves by a combination of chaining and angles at circumference, fully exploiting the theodolite and making a substantial improvement in accuracy and productivity over existing methods.

Rankine's method is named for its discoverer William John Macquorn Rankine at an early stage of his career. He had been working on railways in Ireland, on the construction of the Dublin and Drogheda line.