Murdoch Mackenzie (cartographer)

Murdoch Mackenzie, FRS (1712–1797) was a Scottish hydrographer and cartographer. He is known for his survey of the Orkney Islands: the subsequent maps, known as the Mackenzie Charts are still in use. He is also credited with the invention of the station pointer, a navigational and survey tool used to plot the horizontal angle fixes made with a sextant onto charts.[1]

For the Scottish footballer, see Murdoch McKenzie (footballer). For the Scottish minister, see Murdoch MacKenzie.

Career

Born in Orkney and employed by the Royal Navy, he became the first person to accurately chart the coastline around North Ronaldsay where many vessels had come to grief. He created a measured baseline and established station points along the shore to perform the triangulation equations for the survey. His calculations of latitude were very accurate despite the use of primitive methods compared to today.[2] His work led to the construction of a lighthouse at Dennis Head on North Ronaldsay and his charts are still in use by shipping today. Mackenzie's survey of Orkney was featured in a 2005 episode of Map Man, presented by Nicholas Crane.[3] He invented the station pointer, a tool used for surveying landscapes and making maps after his retirement, and once his nephew took over the coastal surveys. The instrument calculated the position of ships in respect to three stationary points on shore. Two crew members on the ship used Hadley's quadrant to determine their location in accordance with the charts. This method was used to navigate shore lines until the 20th century, but remain as a safety precaution in big maritime vessels.[4]

He also surveyed the north coast of Ireland and the west coast of Scotland, publishing the results in "Nautical description of the west coast of Great Britain from Bristol Channel to Cape Wrath" (1776).[5] His 1774 Treatise on Maritime Surveying included the first use of the term station pointer, noting it as a new instrument and method rather than as Mackenzie's invention or tool.[6] It was first used by his nephew, Lieutenant Murdoch Mackenzie, who succeeded his uncle as a surveyor to the Admiralty, and his assistant Graeme Spence in their surveys of the Thames Estuary.[7]

Personal

He was elected a Fellow of the Royal Society in 1774, and withdrew from the society in 1796.

Death

He died in Minehead, Somerset in 1797, and was buried there on 16 October.[8]

References
  1. "Triangulation adopted by the British". encyclopedia.com. Retrieved 18 April 2012.
  2. "Orcades-A hydrographical survey of the Orkney Islands". odinstone-orkney.co. Retrieved 18 April 2012.
  3. "BBC Two – Map Man – Mackenzie's Chart of the Orkneys". BBC. Retrieved 30 March 2013.
  4. "Triangulation Adopted by the British". Encyclopedia.com. Retrieved 18 April 2012.
  5. "McKenzie; Murdoch (1712–1797)". The Royal Society.
  6. Mackenzie, Murdoch (1774). Treatise on Maritime Surveying in Two Parts: With a Prefatory Essay on Draughts and Surveys of the Sea-coast. E. and C. Dilly.
  7. Fisher, Susanna (1991). "The Origins of the Station Pointer". International Hydrographic Review. 68: 119–126.
  8.  This article incorporates text from a publication now in the public domain: Laughton, John Knox (1893). "McKenzie, Murdoch (d.1797)". In Lee, Sidney (ed.). Dictionary of National Biography. 35. London: Smith, Elder & Co.


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