Surveyor and marine cartographer. Born in Orkney, Mackenzie was educated in Kirkwall. Determined to make good charts around these northern islands, which would prevent the heavy loss of life in what were treacherous waters, he set out to undertake a detailed marine survey from 1742 but crucially recognised the importance of a good land survey as the basis of an accurate sea survey. He published the results of his survey as a fine chart in 1748. To undertake this work he developed new techniques which are described in his Treatise on Maritime Surveying (1774). He was later commissioned by the Admiralty to survey the west coast of Scotland and the north coast of Ireland. He was elected a Fellow of the Royal Society in 1774. He is buried in Minehead in Somerset (England) and is remembered for having set new standards in British hydrographic surveying.