A detailed chart of northeast Borneo and present-day Sulu Archipelago, the Philippines. The chart is dedicated by Dalrymple "to the Right Honourable George Lord Pigot Late Governor of Fort St. George, on the coast of Coromandel in the East Indies..." and "... engraved at his expense". It was included in 'The East India Pilot: a collection of charts, maps and plans for navigation', London, 1770; Dalrymple's rare pilot 'General Introduction to the Charts and Memoirs', 1772; and subsequently published in d'Apres de Mannevillette's 'Le Neptune Oriental'.

The first hydrographer to the British Admiralty, Alexander Dalrymple (1737-1808) is best known for his researches regarding a great Southern Continent, as well as a proponent of the search for the Northwest Passage (thereby influencing Vancouver's survey). Through family connections, Dalrymple was made a "writer" (the most junior position) for the East India Company and sent to Madras where he arrived in May 1753. He was afforded access to Robert Orme's library and grew increasingly fascinated with the EIC's activities in Burma, Indo-China and Borneo. He turned down a promotion so that he might undertake a voyage to the east of his own. ​"In February 1759, Pigot freighted the Cuddalore (Captain George Baker) for Dalrymple ​'to attempt to discover a new route to China through the Molucca Islands and New Guinea'. Dalrymple made three voyages between 1759 and 1764 to the Philippines, Borneo, and Sulu. In the first, based at Canton (Guangzhou), he reconnoitred Borneo, the Philippines, and the coast of Cochin-China. For the second, in the London in 1762, he had James Rennell as companion for a voyage to Sulu and Balambangan, where he had obtained for the company a grant of land. In Madras in 1763 he went through the formality of resignation, confident of reinstatement, to return to London to promote a trading settlement at Balambangan. En route to Canton for passage to England he became provisional deputy governor at Manila for a short period in April 1764, in the aftermath of the treaty of Paris, and he arrived in London in the summer of 1765 …" (ODNB)