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The original draftsman's drawings for the area around St Columb Major in Cornwall, made in 1810. Detail from 1901 Ordnance Survey map of the Imperial fortress colony of Bermuda (showing St. George's Town and St. George's Garrison), compiled from surveys carried out between 1897 and 1899 by Lieutenant Arthur Johnson Savage, Royal Engineers.
An Ordnance Survey cut mark in the UK Occasionally a non-vertical face, and a slightly different mark, was used. The term benchmark, bench mark, or survey benchmark originates from the chiseled horizontal marks that surveyors made in stone structures, into which an angle iron could be placed to form a "bench" for a leveling rod, thus ensuring that a leveling rod could be accurately ...
The Ordnance Survey Drawings are a series of 351 of the original preliminary drawings made by the surveyors of the Ordnance Survey between the 1780s and 1840 in preparation for the publication of the one-inch-to-the-mile "Old Series" of maps of England and Wales.
The Ordnance Survey's first trig point was erected on 18 April 1936 near Cold Ashby, Northamptonshire. In low-lying or flat areas some trig points are only a few metres above sea level and one is even at −1 m (near Little Ouse, Cambridgeshire , TL61718 89787). [ 7 ]
The Ordnance Survey (OS) devised the national grid reference system, and it is heavily used in its survey data, and in maps based on those surveys, whether published by the Ordnance Survey or by commercial map producers. Grid references are also commonly quoted in other publications and data sources, such as guide books and government planning ...
The Ordnance Survey began producing six inch to the mile (1:10,560) maps of Great Britain in the 1840s, modelled on its first large-scale maps of Ireland from the mid-1830s. This was partly in response to the Tithe Commutation Act 1836 which led to calls for a large-scale survey of England and Wales.
An ordnance datum (OD) is a vertical datum used by an ordnance survey as the basis for deriving altitudes on maps. A spot height may be expressed as above ordnance datum ( AOD ). Usually mean sea level (MSL) at a particular place is used for the datum.
Bedrock maps (previously known as solid maps) show the underlying rock, without superficial deposits. The maps are superimposed over a topographic map base produced by Ordnance Survey (OS), and use symbols to represent fault lines, strike and dip or geological units, boreholes etc. Colors are used to represent different geological units ...