Exceptionally detailed, large-scale charts of parts of Southeast Asia and the China Sea, including Singapore, Malay, Borneo, Cambodia, Cochin- China, Hainan, southeast China, Taiwan, and Luzon in the Philippines. The chart boldly indicates the "best" sea-routes to and from Batavia to China, depending on the season, and the condition of the vessel. "The best route towards China for leaky crazy ships during the strength of the S.W. Monsoon" plots a course that hugs the shores of the Malay Peninsula and Cambodia. The islands of the "Sincapour Strait", including "Sincapour", in shown in great detail, with numerous depth soundings, and coastal profiles. Printed updates, to the location of dangerous shoals in particular, appear to 1849.

The current charts were first published in 1821 and 1823, respectively, as part of a plan to monetize his experience by producing a series of charts of the China Sea, Malacca Strait, and Bombay Harbour. Touchingly, the lower sheet shows the "Pedro Branco Light" that was built as a commemoration to Horsburgh upon his death in 1836, at the eastern entrance to the Strait of Singapore.

The map is dedicated to Captain Daniel Ross (1780-1849) and his team of hydrographers of the Bombay Marine. In 1807, Ross was tasked by the East India Company to survey the China Seas. He spent nine years surveying the coast between 1807 and 1816, and then spent a further four years charting the seas between 1816 and 1820. On his return to England in 1821 he was rewarded with a cash sum of £1,500 from the East India Company, for his tireless work out in the Far East. He would later appear before a government Select Committee investigating the possibilities of increasing the Britain's trade with China.

With the tracks of many voyages from the Singapore Strait to Canton, and then on to Manila, plotted, and annotated in the same hand, in pen and different coloured ink, dated: 1856, 1858, 1859, 1860, and 1864.