John Septimus Roe was posted as a master's mate to the surveying service in New South Wales then under the command of Phillip Parker King. He arrived in the colony in September 1817 and conducted three hydrographic coastal surveys over the next three years, which included circumnavigating Australia. He was appointed Lieutenant in April 1822. On this nautical chart which encompasses Port Jackson from the Heads west to 'The Flats' (Homebush Bay), Roe has indicated the soundings or the depth of the harbour, recorded in fathoms. He has noted the tidal changes and the western and eastern channels near the entrance to the Heads.