Rhumb line (loxodrome) (Pedro Nunes)
Loxodromia: línea de rumbo constante (Pedro Nunes)
- Date
- 1537 · confidence high
- Place
- Lisbon, Portugal
- Credited to
- Pedro Nunes
- Field
- Knowledge & symbols
What was discovered
Pedro Nunes showed that sailing on a constant bearing to the meridians traces not a great circle but a spiral winding toward the pole, the rhumb line or loxodrome. He corrected the belief of pilots that a fixed course was the shortest route and laid the ground for Mercator's chart.
The term 'loxodrome' is Snellius's (1624); Nunes describes it in the Tratado da Sphera (1537) and in De arte atque ratione navigandi (1573).
What it led to
- Mercator's projection
- Edward Wright's tables
- the distinction between great-circle and rhumb-line navigation