Finely illustrated sea chart of a portion of the Indian Ocean, highlighting the direction of the ocean currents and prevailing winds in the region.
Important chart illustrating the fastest sailing routes through the region.
The present chart is one of two sea chart illustrating Jacques Raymond Giron de Grenier’s newly discovered faster sailing routes across the Indian Ocean.
During the 1760s and 1770s, Grenier's pioneered new routes through the region which substantially reduced the sailing time from Europe across the Indian Ocean to India and the Straits of Malacca during the Northeast (Winter) Monsoon. A second chart, not present here, illustrates the route during the Southwest (Summer) Monsoon.
The route pioneered by Grenier reduced the transit time by several weeks, a remarkable improvement which significantly reduced the cost of the journey, making Grenier's charts among the most important thematic maps of the 18th Century.