J0825 : Bench Mark, Newry

taken 6 years ago, near to An Tiur and Cloghoge, Northern Ireland

Bench Mark, Newry
Bench Mark, Newry
Pivot bench mark on the eastern corner of the Dublin Road bridge across the Newry River in the city (see J0825 : Bench Mark, Newry for a detailed view). This mark dates from the 1st levelling of Ireland which took place in 1839-43. It is the 152nd mark in a line of 298 which stretches from Dublin (starting at Buckingham Lock LinkExternal link ) to Belfast (ending at J3474 : Bench Mark, Belfast). The original remarks for the mark describe it as "Mark on South battlement of Dublin Bridge, Newry; 6.4 feet above lower surface of keystone". It was originally levelled to 29.332 feet above sea level.
Today the mark has been levelled to 6.34 metres above MSL.

The billboard advertisement in the background is for the Victoria Square shopping centre in Belfast J3474 : Victoria Square, Belfast.
Bench Mark
Bench marks were historically used to record the height above sea level of a location as surveyed against the Mean Sea Level data (taken at Clarendon Dock, Belfast, for Northern Ireland data, Newlyn in Cornwall for data in Great Britain and Portmoor Pier, Malin Head, for data relating to the Republic of Ireland). They were used as part of a greater surveying network by the UK Ordnance Survey, Ordnance Survey Northern Ireland (OSNI) and the Ordnance Survey Ireland (OSI). If the exact height of one bench mark is known then the exact height of the next can be found by measuring the difference in heights, through a process of spirit levelling. In this way hundreds of thousands of bench marks were sited all around the UK & Ireland from the mid 19th to late 20th centuries. There are several distinct types of bench mark:

- Fundamental bench marks have been constructed at selected sites where foundations can be set on stable strata such as bedrock. Each FBM consists of a buried chamber with a brass bolt set in the top of a granite pillar. See NG8825 : Dornie fundamental bench mark for an example. FBMs were used in Ireland as well as GB but those in Ireland do not have any surface markers, nor are they marked on standard maps.
- Flush brackets consist of metal plates about 90 mm wide and 175 mm long. Each bracket has a unique serial number. They are most commonly found on most Triangulation Pillars, some churches or on other important civic buildings. See J3270 : Flush Bracket, Belfast for an example.
- Cut bench marks are the commonest form of mark. They consist of a horizontal bar cut into a wall or brickwork and are found just about anywhere. A broad arrow is cut immediately below the centre of the horizontal bar. See J3372 : Bench Mark, Belfast for an example. The horizontal mark may be replaced by or contain a bolt - see J1486 : Bench Mark, Antrim.
Other marks include:
- Projecting bench marks such as SD8072 : Projecting Bracket Benchmark on St Oswald's Tower
- Bolt bench marks such as SJ1888 : OSBM bolt on Hilbre Island
- Rivet bench marks such as J3978 : Bench Mark, Holywood
- Pivot bench marks such as SJ2661 : Pivot bench mark on Leeswood Bridge

Bench marks are commonly found on older buildings or other semi-permanent features such as stone bridges or walls. Due to updated mapping techniques and technological advances such as GPS, bench marks are no longer maintained. Many are still in existence and the markers will probably remain until they are eventually destroyed by redevelopment or erosion.
Creative Commons Licence [Some Rights Reserved]   © Copyright Rossographer and licensed for reuse under this Creative Commons Licence.
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Grid Square
J0825, 203 images   (more nearby )
  (find more nearby)
Date Taken
Wednesday, 4 December, 2013   (more nearby)
Sunday, 8 December, 2013
Geographical Context
Historic sites and artefacts  City, Town centre 
Place (from Tags)
Subject Location
Irish: geotagged! J 085 259 [100m precision]
WGS84: 54:10.2769N 6:20.3229W
Camera Location
Irish: geotagged! J 085 259
View Direction
West-southwest (about 247 degrees)
Clickable map

Other Tags
O.S. Benchmark  Newry  OSNI  Ordnance Survey Bench Mark  Bench Mark  Bridge  Pivot Bench Mark 

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Image classification(about): Geograph (Fourth Visitor for J0825)
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