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| Recorded mountains to 1700 |
John de Courcy has detailed the summits that appear on maps up to 1700.
(see Mountaineering Ireland. IMEHS Journal, Vol 2, 2005)
Charles Vallencey produced a military survey
of parts of the island around 1780.
Various land owners produced estate maps of their property and it was William Edgeworth, who had been involved in the bog survey, that produced a trigonometrical survey of Co Longford and part of Roscommon. With him, 'native Irish cartography attained a new high level'.
In 1824 the six-inch Ordnance Survey mapping of Ireland was begun. As a consequence the surveyors were the first group to systematically get to all the significant mountain summits on the island.
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| Principal triangulation with dates. |
Much discussion took place as to the merits of contour lines or hachuring to represent altitude and slope and it was not until about 1890 that the complete hill edition was produced.
A full account of the operation and proceedings of the OS in 19th Century Ireland is given by JH Andrews in A Paper Landscape.
Thomas Colby was the director of the OS in Ireland and John O' Donovan played
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| John O'Donovan |
an important role in the toponymical aspects of the survey.
Of course, the surveyors climbed the mountains for professional reasons rather than for recreation. However, their activities may have had an influence on a generation of people that became interested in the activity of surveying, some of whom carried this interest abroad to Europe and North America and carried out surveys of their own in these places. Among such people were John Palliser, Anthony Adams Reilly, Edward Oliver Wheeler and there will be more about these to follow.
A fascinating 'biography of the Ordnance Survey' is Map of a Nation by Rachel Hewitt (Granta, 2010)
