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, nativename_a = , nativename_r = , logo = Ordnance Survey 2015 Logo.svg , logo_width = 240px , logo_caption = , seal = , seal_width = , seal_caption = , picture = , picture_width = , picture_caption = , formed = , preceding1 = , dissolved = , superseding = , jurisdiction = Great BritainThe Ordnance Survey deals only with maps of Great Britain, and, to an extent, the
Isle of Man ) , anthem = " O Land of Our Birth" , image = Isle of Man by Sentinel-2.jpg , image_map = Europe-Isle_of_Man.svg , mapsize = 290px , map_alt = Location of the Isle of Man in Europe , map_caption = Location of the Isle of Man (green) in E ...

Isle of Man
, but not Northern Ireland, which has its own, separate government agency, the
Ordnance Survey of Northern Ireland Ordnance may refer to: Military and defense * Ordnance items in military logistics Military logistics is the discipline of planning and carrying out the movement, supply, and maintenance of military forces. In its most comprehensive sense, it is ...
.
, headquarters =
Southampton Southampton () is a port A port is a facility comprising one or more or loading areas, where ships load and discharge and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, su ...
, England, UK , region_code = GB , coordinates = , employees = 1,244 , budget = , minister1_name = , minister1_pfo = , chief1_name = Steve Blair , chief1_position =
CEO A chief executive officer (CEO), chief administrator officer, or just chief executive (CE), is one of a number of Corporate Executive, corporate executives in charge of managing an organization especially an independent Legal person, legal entity ...
, agency_type = , parent_agency = , child1_agency = , keydocument1 = , website = , footnotes = , map = , map_width = , map_caption = Ordnance Survey (OS) is the
national mapping agency A national mapping agency is an organisation, usually publicly owned, that produces topographic map Topography concerns the shape and character of the Earth's surface, and maps were among the first artifacts to record these observations. In mod ...
for Great Britain. The agency's name indicates its original military purpose (see
ordnance Ordnance may refer to: Military and defense * Ordnance items in military logistics Military logistics is the discipline of planning and carrying out the movement, supply, and maintenance of military forces. In its most comprehensive sense, it is ...

ordnance
and
surveying Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions of points and the distances and angles between them. A land surveying professional is called a land surveyo ...

surveying
), which was to map Scotland in the wake of the
Jacobite rising of 1745 The Jacobite rising of 1745, also known as the Forty-five Rebellion or simply the '45 ( gd, Bliadhna Theàrlaich, , ), was an attempt by Charles Edward Stuart Charles Edward Louis John Casimir Sylvester Severino Maria Stuart (20 December ...
. There was also a more general and nationwide need in light of the potential threat of invasion during the
Napoleonic Wars The Napoleonic Wars (1803–1815) were a series of major global conflicts pitting the French Empire#REDIRECT French Empire {{Redirect shell , {{R from ambiguous page {{R from other capitalisation ... and its allies, led by Napoleon I ...
. Since 1 April 2015 Ordnance Survey has operated as Ordnance Survey Ltd, a
government-owned company A state-owned enterprise (SOE) or government-owned enterprise (GOE) is a business enterprise Business is the activity of making one's living or making money by producing or buying and selling Product (business), products (such as goods a ...
, 100% in public ownership. The Ordnance Survey Board remains accountable to the
Secretary of State for Business, Energy and Industrial Strategy The Secretary of State for Business, Energy and Industrial Strategy, also referred to as the Business Secretary, is a senior Minister of the Crown Minister of the Crown is a formal constitutional term used in Commonwealth realms to describ ...
. It was also a member of the
Public Data Group The Public Data Group (PDG) was a grouping of data providing organisations owned by the UK government The Government of the United Kingdom, domestically referred to as Her Majesty's Government, is the central government of the United Kingdom ...
. Paper maps for walkers represent only 5% of the company's annual revenue. They produce digital map data, online route planning and sharing services and mobile apps, plus many other location-based products for business, government and consumers. Ordnance Survey mapping is usually classified as either " large-scale" (in other words, more detailed) or "small-scale". The Survey's large-scale mapping comprises 1:2,500 maps for urban areas and 1:10,000 more generally. (The latter superseded the 1:10,560 "six
inch Measuring tape with inches The inch (symbol: in or ″) is a unit Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete pi ...
es to the
mile The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a imperial unit, British imperial unit and US customary unit of distance; both are based on the older English unit of Unit of length, length eq ...
" scale in the 1950s.) These large scale maps are typically used in professional
land-use caused by numerous roads near the Indiana Dunes National Lakeshore Land use involves the management and modification of natural environment or wilderness Wilderness or wildlands (usually in the plural), are natural environments on Earth ...
contexts and were available as sheets until the 1980s, when they were digitised. Small-scale mapping for leisure use includes the 1:25,000 "Explorer" series, the 1:50,000 "Landranger" series and the 1:250,000 road maps. These are still available in traditional sheet form. Ordnance Survey maps remain in
copyright Copyright is a type of intellectual property Intellectual property (IP) is a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more ...

copyright
for fifty years after their publication. Some of the
Copyright Libraries
Copyright Libraries
hold complete or near-complete collections of pre-digital OS mapping.


Origins

The origins of the Ordnance Survey lie in the aftermath of the
Jacobite rising of 1745 The Jacobite rising of 1745, also known as the Forty-five Rebellion or simply the '45 ( gd, Bliadhna Theàrlaich, , ), was an attempt by Charles Edward Stuart Charles Edward Louis John Casimir Sylvester Severino Maria Stuart (20 December ...
.
Prince William, Duke of Cumberland Prince William Augustus, Duke of Cumberland, (15 April 1721 Old_Style_and_New_Style_dates">N.S..html" ;"title="Old_Style_and_New_Style_dates.html" ;"title="/nowiki>Old Style and New Style dates">N.S.">Old_Style_and_New_Style_dates.html" ;"title= ...
realised that the British Army did not have a good map of the
Scottish Highlands The Highlands ( sco, the Hielands; gd, a’ Ghàidhealtachd , 'the place of the ') is a historic region of . Culturally, the Highlands and the diverged from the later into the , when replaced throughout most of the Lowlands. The term is al ...

Scottish Highlands
to locate Jacobite dissenters such as
Simon Fraser, 11th Lord Lovat Simon Fraser, 11th Lord Lovat (c. 1667 – 9 April 1747, London), nicknamed 'the Fox', was a Scottish Jacobite and Chief of Clan Fraser of Lovat, known for his feuding and changes of allegiance. In 1715, he had been a supporter of the Hou ...
so that they could be put on trial. In 1747, Lieutenant-Colonel David Watson proposed the compilation of a map of the Highlands to help to subjugate the clans. In response, King George II charged Watson with making a military survey of the Highlands under the command of the Duke of Cumberland. Among Watson's assistants were
William Roy Major-General William Roy (4 May 17261 July 1790) was a Scottish military engineer, surveyor, and antiquarian 's cabinet of curiosities, from ''Museum Wormianum,'' 1655 An antiquarian or antiquary (from the Latin: ''antiquarius'', meaning ...
,
Paul Sandby Paul Sandby (1731 – 7 November 1809) was an English map-maker turned Landscape art, landscape painter in watercolours, who, along with his older brother Thomas Sandby, Thomas, became one of the founding members of the Royal Academy in 1768 ...
and John Manson. The survey was produced at a scale of 1 inch to 1000 yards (1:36,000) and included "the Duke of Cumberland's Map" (primarily by Watson and Roy), now held in the
British Library The British Library is the national library A national library is a library A library is a curated collection of sources of information and similar resources, made accessible to a defined community for reference or borrowing. It provid ...

British Library
. Roy later had an illustrious career in the
Royal Engineers The Corps of Royal Engineers, usually just called the Royal Engineers (RE), and commonly known as the ''Sapper A sapper, also called pioneer or combat engineer, is a combatant Combatant is the legal status of an individual who has the ri ...
(RE), rising to the rank of General, and he was largely responsible for the British share of the work in determining the relative positions of the French and British royal observatories. This work was the starting point of the
Principal Triangulation of Great Britain The Principal Triangulation of Britain was the first high-precision trigonometric survey of the whole of Great Britain (including Ireland), carried out between 1791 and 1853 under the auspices of the Board of Ordnance. The aim of the survey was ...
(1783–1853), and led to the creation of the Ordnance Survey itself. Roy's technical skills and leadership set the high standard for which Ordnance Survey became known. Work was begun in earnest in 1790 under Roy's supervision, when the
Board of Ordnance The Board of Ordnance was a British government The Government of the United Kingdom, domestically referred to as Her Majesty's Government, is the central government of the United Kingdom of Great Britain and Northern Ireland.Ministry of DefenceMinistry of Defence or Ministry of Defense may refer to: * Ministry of defence, a type of government department responsible for matters of defence Current ministries * Ministry of Defense (Afghanistan) * Ministry of Defence (Albania) * Ministry ...
) began a national military survey starting with the south coast of England. Roy's birthplace near
Carluke The town of Carluke (; gd, Cathair MoLuaig) lies in the heart of the Lanarkshire countryside in South Lanarkshire, Scotland Scotland ( sco, Scotland, gd, Alba ) is a Countries of the United Kingdom, country that is part of the United King ...
in
South Lanarkshire South Lanarkshire ( sco, Sooth Lanrikshire; gd, Siorrachd Lannraig a Deas) is one of 32 Council areas of Scotland, unitary authorities of Scotland. It borders the south-east of the Glasgow City Council, City of Glasgow and contains some of Great ...
is today marked by a memorial in the form of a large OS trig point. By 1791 the Board received the newer
Ramsden theodolite The Ramsden surveying instruments are those constructed by Jesse Ramsden and used in high precision geodetic surveys carried out in the period 1784 to 1853. This includes the five great theodolite A theodolite is a precision optical instrument ...
(an improved successor to the one that Roy had used in 1784), and work began on mapping southern Great Britain using a five-mile baseline on
Hounslow Heath Hounslow Heath is a local nature reserve in the London Borough of Hounslow The London Borough of Hounslow () is a London borough in West London (sub region), West London, England, forming part of Outer London. It was created in 1965 when three ...
that Roy himself had previously measured; it crosses the present
Heathrow Airport Heathrow Airport (), originally called ''London Airport'' until 1966 and now known as London Heathrow , is a major international airport in London, England. With Gatwick Airport, Gatwick, London City Airport, City, Luton Airport, Luton, Stanste ...

Heathrow Airport
. In 1991
Royal Mail Royal Mail Group plc is a British multinational and company, originally established in 1516 as a department of the English government. The company's subsidiary Royal Mail Group Limited operates the brands Royal Mail (letters and parcels) and (pa ...

Royal Mail
marked the bicentenary by issuing a set of postage stamps featuring maps of the Kentish village of
Hamstreet Hamstreet is a village in Kent Kent is a Counties of England, county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west. The county also shares ...

Hamstreet
. In 1801 the first one-inch-to-the-mile (1:63,360 scale) map was published, detailing the county of
Kent Kent is a county A county is a geographical region of a country used for administrative or other purposesChambers Dictionary, L. Brookes (ed.), 2005, Chambers Harrap Publishers Ltd, Edinburgh in certain modern nations. The term is derived ...

Kent
, with
Essex Essex () is a county A county is a geographical region of a country used for administrative or other purposesChambers Dictionary The ''Chambers Dictionary'' (''TCD'') was first published by William Chambers (publisher), William and Rob ...

Essex
following shortly afterwards. The Kent map was published privately and stopped at the county border, while the Essex maps were published by Ordnance Survey and ignore the county border, setting the trend for future Ordnance Survey maps. In the next 20 years about a third of England and Wales was mapped at the same scale (see
Principal Triangulation of Great Britain The Principal Triangulation of Britain was the first high-precision trigonometric survey of the whole of Great Britain (including Ireland), carried out between 1791 and 1853 under the auspices of the Board of Ordnance. The aim of the survey was ...
) under the direction of
William Mudge William Mudge (1762–1820) was an English artillery officer and surveyor, born in Plymouth Plymouth () is a port city status in the United Kingdom, city in England on the south coast of Devon, approximately south-west of Exeter and west-sou ...

William Mudge
, as other military matters took precedence. It took until 1823 to re-establish the relationship with the French survey made by Roy in 1787. By 1810 one inch to the mile maps of most of the south of England were completed, but they were withdrawn from sale between 1811 and 1816 because of security fears. By 1840 the one-inch survey had covered all of Wales and all but the six northernmost counties of England. Surveying was hard work. For instance, Major Thomas Colby, the longest-serving Director General of Ordnance Survey, walked in 22 days on a reconnaissance in 1819. In 1824, Colby and most of his staff moved to Ireland to work on a six-inches-to-the-mile (1:10,560) valuation survey. The survey of Ireland, county by county, was completed in 1846. The suspicions and tensions it caused in rural Ireland are the subject of
Brian Friel Brian Patrick Friel (9 January 1929 – 2 October 2015) was an Irish dramatist, short story writer and founder of the Field Day Theatre Company. He had been considered one of the greatest living English-language dramatists. (subscription required) ...

Brian Friel
's play ''
Translations Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''transla ...
''. Colby was not only involved in the design of specialist measuring equipment. He also established a systematic collection of place names, and reorganised the map-making process to produce clear, accurate plans. Place names were recorded in "Name Books", a system first used in Ireland. The instructions for their use were: Whilst these procedures generally produced excellent results, mistakes were made: for instance, the
Pilgrims' Way The Pilgrims' Way (also Pilgrim's Way or Pilgrims Way) is the historical route supposedly taken by pilgrims from Winchester, Hampshire, Winchester in Hampshire, England, to the shrine of Thomas Becket at Canterbury in Kent. This name, of compara ...
in the
North Downs The North Downs are a ridge of chalk hills in south east England that stretch from Farnham in Surrey to the White Cliffs of Dover in Kent. Much of the North Downs comprises two Area of Outstanding Natural Beauty, Areas of Outstanding Natural Bea ...
labelled the wrong route, but the name stuck. Similarly, the spelling of
Scafell Scafell ( or ; also spelled Sca Fell, previously Scawfell) is a mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. A mountain differs from a plateau in havi ...
and
Scafell Pike Scafell Pike () is the highest and the most prominent mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. A mountain differs from a plateau in having a limited s ...

Scafell Pike
copied an error on an earlier map, and was retained as this was the name of a corner of one of the Principal Triangles, despite "Scawfell" being the almost universal form at the time. Colby believed in leading from the front, travelling with his men, helping to build camps and, as each survey session drew to a close, arranging mountain-top parties with enormous s. The
British Geological Survey The British Geological Survey (BGS) is a partly publicly funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its continental shelf by means of systematic surveying, monitoring and research. The BGS hea ...

British Geological Survey
was founded in 1835 as the Ordnance Geological Survey under
Henry De la Beche Sir Henry Thomas De la Beche KCB, FRS (10 February 179613 April 1855) was an English geologist and palaeontologist Paleontology, also spelled palaeontology or palæontology (), is the scientific study of life that existed prior to, and som ...
, and remained a branch of the Ordnance Survey until 1965. At the same time the uneven quality of the English and Scottish maps was being improved by engravers under Benjamin Baker. By the time Colby retired in 1846, the production of six-inch maps of Ireland was complete. This had led to a demand for similar treatment in England, and work was proceeding on extending the six-inch map to northern England, but only a three-inch scale for most of Scotland. When Colby retired he recommended
William Yolland William Yolland CB, FRS FRSA Fellowship of the Royal Society for the Encouragement of Arts, Manufactures and Commerce (FRSA) is an award granted to individuals that the Royal Society of Arts (RSA) judges to have made outstanding achievements to ...
as his successor, but he was considered too young and the less experienced Lewis Alexander Hall was appointed. After a fire in the
Tower of London The Tower of London, officially Her Majesty's Royal Palace and Fortress of the Tower of London, is a historic castle in East Sussex East Sussex is a county A county is a geographical region of a country used for administrative ...

Tower of London
, the headquarters of the survey was moved to
Southampton Southampton () is a port A port is a facility comprising one or more or loading areas, where ships load and discharge and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, su ...
, and Yolland was put in charge, but Hall sent him off to Ireland so that when Hall left in 1854 Yolland was again passed over in favour of Major
Henry James Henry James ( – ) was an American-British author. He is regarded as a key transitional figure between literary realism Literary realism is a literary genre, part of the broader realism (arts), realism in arts, that attempts to represent subj ...
. Hall was enthusiastic about extending the survey of the north of England to a scale of 1:2,500. In 1855, the Board of Ordnance was abolished and the Ordnance Survey was placed under the
War Office The War Office This article contains text from this source, which is available under th Open Government Licence v3.0 © Crown copyright was a Department of the British Government responsible for the administration of the British Army The ...
together with the Topographical Survey and the Depot of Military Knowledge. Eventually in 1870 it was transferred to the
Office of Works The Office of Works was established in the English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, which h ...
. The primary triangulation of the United Kingdom of Roy, Mudge and Yolland was completed by 1841, but was greatly improved by
Alexander Ross Clarke Col Alexander Ross Clarke Royal Society of London, FRS FRSE (1828–1914) was a British geodesist, primarily remembered for his calculation of the Principal Triangulation of Britain (1858), the calculation of the Figure of the Earth (1858, 186 ...

Alexander Ross Clarke
who completed a new survey based on 's spheroid in 1858, completing the Principal Triangulation. The following year, he completed an initial
levelling Levelling (British English British English (BrE) is the standard dialect of the English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, w ...
of the country.


Great Britain "County Series"

After the Ordnance Survey published its in the mid-1830s, the
Tithe Commutation Act 1836 The Tithe Commutation Act 1836 (6 & 7 Will 4 c 71) was an Act of the Parliament of the United Kingdom The Parliament of the United Kingdom is the Parliamentary sovereignty in the United Kingdom, supreme Legislature, legislative body of the U ...
led to calls for a similar six-inch to the mile survey in England and
Wales Wales ( cy, Cymru ) is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the land of an individual's birth, residence or citizenship. A country may be an independent sovereign ...

Wales
. Official procrastination followed, but the development of the railways added to pressure that resulted in the Ordnance Survey Act 1841. This granted a right to enter property for the purpose of the survey. Following a fire at its headquarters at the
Tower of London The Tower of London, officially Her Majesty's Royal Palace and Fortress of the Tower of London, is a historic castle in East Sussex East Sussex is a county A county is a geographical region of a country used for administrative ...

Tower of London
in 1841 the Ordnance Survey relocated to a site in
Southampton Southampton () is a port A port is a facility comprising one or more or loading areas, where ships load and discharge and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, su ...
and was in disarray for several years, with arguments about which scales to use. Major-General Sir
Henry James Henry James ( – ) was an American-British author. He is regarded as a key transitional figure between literary realism Literary realism is a literary genre, part of the broader realism (arts), realism in arts, that attempts to represent subj ...
was by then Director General, and he saw how photography could be used to make maps of various scales cheaply and easily. He developed and exploited
photozincographyPhotozincography, sometimes referred to as heliozincography but essentially the same process, known commercially as zinco, is the photographic process developed by Sir Henry James FRS (1803–1877) in the mid-nineteenth century. This method en ...
, not only to reduce the costs of map production but also to publish
facsimile '', a famous illuminated manuscript An illuminated manuscript is a formally prepared document A document is a written Writing is a medium of human communication Communication (from Latin ''communicare'', meaning "to share") is the a ...
s of nationally important manuscripts. Between 1861 and 1864, a facsimile of the
Domesday Book Domesday Book () – the spelling of "Doomsday Book" – is a manuscript record of the "Great Survey" of much of England and parts of Wales completed in 1086 by order of William I, known as . Domesday has long been associated with the Latin p ...
was issued,
county A county is a geographical region of a country used for administrative or other purposesChambers Dictionary The ''Chambers Dictionary'' (''TCD'') was first published by William Chambers (publisher), William and Robert Chambers (publisher bo ...
by county; and a facsimile of the
Gough Map The Gough Map or Bodleian Map is a Late Middle Ages, Late Medieval map of the island of Great Britain. Its precise dates of production and authorship are unknown. It is named after Richard Gough (antiquarian), Richard Gough, who bequeathed the map ...
was issued in 1870. From the 1840s, the Ordnance Survey concentrated on the Great Britain " County Series", modelled on the earlier Ireland survey. A start was made on mapping the whole country, county by county, at six inches to the mile (1:10,560). In 1854, "twenty-five inch" maps were introduced with a scale of 1:2500 (25.344 inches to the mile) and the six inch maps were then based on these twenty-five inch maps. The first edition of the two scales was completed by the 1890s, with a second edition completed in the 1890s and 1900s. From 1907 till the early 1940s, a third edition (or "second revision") was begun but never completed: only areas with significant changes on the ground were revised, many two or three times. Meanwhile, publication of the one-inch to the mile series for Great Britain was completed in 1891. From the late 19th century to the early 1940s, the OS produced many "restricted" versions of the County Series maps and other War Department sheets for
War Office The War Office This article contains text from this source, which is available under th Open Government Licence v3.0 © Crown copyright was a Department of the British Government responsible for the administration of the British Army The ...
purposes, in a variety of large scales that included details of military significance such as dockyards, naval installations, fortifications and military camps. Apart from a brief period during the disarmament talks of the 1930s, these areas were left blank or incomplete on standard maps. The War Department 1:2500s, unlike the standard issue, were contoured. The de-classified sheets have now been deposited in some of the Copyright Libraries, helping to complete the map-picture of pre-Second World War Britain.


City and town mapping, 19th and early 20th century

From 1824, the OS began a 6-inch (1:10,560) survey of Ireland for taxation purposes but found this to be inadequate for urban areas and adopted the five-foot scale (1:1056) for Irish cities and towns. From 1840, the six-inch standard was adopted in Great Britain for the un-surveyed northern counties and the 1:1056 scale also began to be adopted for urban surveys. Between 1842 and 1895, some 400 towns were mapped at 1:500 (126 inches), 1:528 (120 inches, "10 foot scale") or 1:1056 (60 inches), with the remaining towns mapped at 1:2500 (~25 inches). In 1855, the Treasury authorised funding for 1:2500 for rural areas and 1:500 for urban areas. The 1:500 scale was considered more 'rational' than 1:528 and became known as the "sanitary scale" since its primary purpose was to support establishment of mains sewerage and water supply. However, a review of the Ordnance Survey in 1892 found that sales of the 1:500 series maps were very poor and the Treasury declined to fund their continuing maintenance, declaring that any revision or new mapping at this scale must be self-financing. Very few towns and cities saw a second edition of the town plans: by 1909 only fourteen places had paid for updates. The review determined that revision of 1:2500 mapping should proceed apace. The most detailed mapping of London was the OS's 1:1056 survey between 1862 and 1872, which took 326 sheets to cover the capital; a second edition (that needed 759 sheets due to urban expansion) was completed and brought out between 1891 and 1895. London was unusual in that
land registration Land registration is any of various systems by which matters concerning ownership Ownership is the state or fact of exclusive rights and control over property, which may be any asset, including an object, land or real estate, intellectual proper ...
on transfer of title was made compulsory there in 1900. The 1:1056 sheets were partially revised to provide a basis for
HM Land Registry , nativename_a = , nativename_r = , logo = HM_Land_Registry.png , logo_width = 225px , logo_caption = , seal = , seal_width = , seal_caption = , picture = , picture_width = , picture_caption = , formed = , preceding1 = , ...
index maps and the OS mapped the whole London County Council area (at 1:1056) at national expense. From 1911 onwardsand mainly between 1911 and 1913the Ordnance Survey photo-enlarged many 1:2500 sheets covering built-up areas to 1:1250 (50.688 inches to the mile) for Land Valuation and Inland Revenue purposes: the increased scale was to provide space for annotations. About a quarter of these 1:1250s were marked "Partially revised 1912/13". In areas where there were no further 1:2500s, these partially revised "fifty inch" sheets represent the last large-scale revision (larger than six-inch) of the County Series. The County Series mapping was superseded by the
Ordnance Survey National Grid The Ordnance Survey National Grid reference system (also known as British National Grid (BNG)) is a system of geographic grid reference A projected coordinate system, also known as a projected coordinate reference system, a planar coordin ...

Ordnance Survey National Grid
1:1250s, 1:2500s and 1:10,560s after the Second World War.


20th century

During World War I, the Ordnance Survey was involved in preparing maps of
France France (), officially the French Republic (french: link=no, République française), is a List of transcontinental countries, transcontinental country spanning Western Europe and Overseas France, overseas regions and territories in the Ame ...
and
Belgium Belgium ( nl, België ; french: Belgique ; german: Belgien ), officially the Kingdom of Belgium, is a country in Western Europe Western Europe is the western region of Europe. The region's countries and territories vary depending on cont ...
. During World War II, many more maps were created, including: * 1:40,000 map of
Antwerp Antwerp (; nl, Antwerpen ; french: Anvers ) is a city in Belgium and the capital of Antwerp (province), Antwerp province in the Flemish Region. With a population of 520,504,
Antwerp
, Belgium * 1:100,000 map of
Brussels Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Brusse ...

Brussels
, Belgium * 1:5,000,000 map of
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. With over Demographics of South Africa, 60 million people, it is the world's List of countries by population, 23rd-most ...
* 1:250,000 map of
Italy Italy ( it, Italia ), officially the Italian Republic ( it, Repubblica Italiana, links=no ), is a country consisting of Italian Peninsula, a peninsula delimited by the Alps and List of islands of Italy, several islands surrounding it, whose ...
* 1:50,000 map of north-east France * 1:30,000 map of the Netherlands with manuscript outline of districts occupied by the
German Army The German Army () is the land component of the armed forces of Federal Republic of Germany, Germany. The present-day German Army was founded in 1955 as part of the newly formed West German ''Bundeswehr'' together with the German Navy, ''Marine' ...
. After the war, Colonel
Charles Close Colonel Sir Charles Frederick Arden-Close, (10 August 1865 – 19 December 1952) was a British geographer and Surveying, surveyor. He was Director-general, Director General of the Ordnance Survey from 1911 to 1922. His insistence on attention ...
, then Director General, developed a strategy using covers designed by Ellis Martin to increase sales in the leisure market. In 1920 O. G. S. Crawford was appointed Archaeology Officer and played a prominent role in developing the use of aerial photography to deepen understanding of archaeology. In 1922, devolution to Northern Ireland led to the creation of
Ordnance Survey of Northern Ireland Ordnance may refer to: Military and defense * Ordnance items in military logistics Military logistics is the discipline of planning and carrying out the movement, supply, and maintenance of military forces. In its most comprehensive sense, it is ...
(OSNI) and independence of the
Irish Free State The Irish Free State ( ga, Saorstát Éireann, , ; 6 December 192229 December 1937) was a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of St ...
led to the creation of the
Ordnance Survey of Ireland Ordnance Survey Ireland (OSI; ga, Suirbhéireacht Ordanáis Éireann) is the national mapping agency of Ireland Ireland (; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, North Atlantic. It ...
, so the original Ordnance Survey pulled its coverage back to Great Britain. In 1935, the Davidson Committee was established to review the Ordnance Survey's future. The new Director General, Major-General Malcolm MacLeod, started the
retriangulation of Great Britain__NOTOC__ The retriangulation of Great Britain was a triangulation In trigonometry and geometry Geometry (from the grc, γεωμετρία; ''wikt:γῆ, geo-'' "earth", ''wikt:μέτρον, -metron'' "measurement") is, with arithmetic, ...
, an immense task involving the erection of concrete triangulation pillars ("trig points") on prominent hilltops as infallible positions for theodolites. Each measurement made by theodolite during the retriangulation was repeated no fewer than 32 times. The Davidson Committee's final report set the Ordnance Survey on course for the 20th century. The metric was launched and a 1:25000-scale series of maps was introduced. The one-inch maps continued to be produced until the 1970s, when they were superseded by the 1:50000-scale seriesas proposed by William Roy more than two centuries earlier. Ordnance Survey had outgrown its site in the centre of Southampton (made worse by the bomb damage of the Second World War). The bombing during the
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devastated Southampton in November 1940 and destroyed most of Ordnance Survey's city centre offices. Staff were dispersed to other buildings and to temporary accommodation at Chessington and Esher, Surrey, where they produced 1:25000 scale maps of France, Italy, Germany and most of the rest of Europe in preparation for its invasion. Until 1969, Ordnance Survey largely remained at its Southampton city centre HQ and at temporary buildings in the suburb of Maybush nearby, when a new purpose-built headquarters was opened in Maybush adjacent to the wartime temporary buildings there. Some of the remaining buildings of the original Southampton city-centre site are now used as part of the city's court complex. The new head office building was designed by the Ministry of Works (United Kingdom), Ministry of Public Buildings and Works for 4000 staff, including many new recruits who were taken on in the late 1960s and early 1970s as draughtsmen and surveyors. The buildings originally contained factory-floor space for photographic processes such as heliozincography and map printing, as well as large buildings for storing flat maps. Above the industrial areas were extensive office areas. The complex was notable for its concrete mural by sculptor Keith McCarter and the concrete elliptical paraboloid shell roof over the staff restaurant building. In 1995, Ordnance Survey digitised the last of about 230,000 maps, making the United Kingdom the first country in the world to complete a programme of large-scale electronic mapping. By the late 1990s technological developments had eliminated the need for vast areas for storing maps and for making printing plates by hand. Although there was a small computer section at Ordnance Survey in the 1960s, the digitising programme had replaced the need for printing large-scale maps, while computer-to-plate technology (in the form of a single machine) had also rendered the photographic platemaking areas obsolete. Part of the latter was converted into a new conference centre in 2000, which was used for internal events and also made available for external organisations to hire. The Ordnance Survey became an Executive Agency in 1990, making the organisation independent of ministerial control. In 1999 the agency was designated a trading fund, required to cover its costs by charging for its products and to remit a proportion of its profits to the Treasury.


21st century

In 2010, OS announced that printing and warehouse operations were to be outsourced, ending over 200 years of in-house printing. The Frome-based firm Butler, Tanner and Dennis (BT&D) secured its printing contract. As already stated, large-scale maps had not been printed at Ordnance Survey since the common availability of Geographic information system, geographical information systems (GISs), but, until late 2010, the ''OS Explorer'' and ''OS Landranger'' series were printed in Maybush. In April 2009 building began of a new head office in Adanac Park on the outskirts of Southampton. By 10 February 2011 virtually all staff had relocated to the new "Explorer House" building and the old site had been sold off and redeveloped. Prince Philip, Duke of Edinburgh, Prince Philip officially opened the new headquarters building on 4 October 2011. On 22 January 2015 plans were announced for the organisation to move from a trading fund model to a government-owned limited company, with the move completed in April 2015. The organisation remains fully owned by the UK government and retains many of the features of a public organisation. In September 2015 the history of the Ordnance Survey was the subject of a BBC Four TV documentary entitled ''A Very British Map: The Ordnance Survey Story''. On 10 June 2019 the Department for Business, Energy and Industrial Strategy (BEIS) appointed Steve Blair as the Chief Executive of Ordnance Survey. Ordnance Survey supported the launch of the Slow Ways initiative, which encourages users to walk on lesser used paths between UK towns.


GB map range

Ordnance Survey produces a large range of paper maps and digital mapping products.


OS MasterMap

Ordnance Survey's flagship digital product, launched in November 2001, is ''OS MasterMap'', a database that records, in one continuous digital map, every fixed feature of Great Britain larger than a few metres. Every feature is given a unique TOID (TOpographical IDentifier), a simple identifier that includes no semantic information. Typically, each TOID is Polygon mesh, associated with a polygon that represents the area on the ground that the feature covers, in Ordnance Survey National Grid, National Grid coordinates. OS MasterMap is offered in themed layers, each linked to a number of TOIDs. In September 2010, the layers were: ; Topography : The primary layer of ''OS MasterMap'', consisting of vector data comprising large-scale representation of features in the real world, such as buildings and areas of vegetation. The features captured and the way they are depicted is listed in a specification available on the Ordnance Survey website. ; Integrated transport network : A link-and-node network of transport features such as roads and railways. This data is at the heart of many Satellite navigation, satnav systems. In an attempt to reduce the number of Heavy goods vehicle, HGVs using unsuitable roads, a data-capture programme of "Road Routing Information" was undertaken by 2015, aiming to add information such as height restrictions and one-way streets. ; Imagery : Orthophoto, Orthorectified aerial photography in raster format. ; Address : An overlay adding every address in the UK to other layers. ; Address 2 : Adds further information to the Address layer, such as addresses with multiple occupants (blocks of flats, student houses, etc.) and objects with no postal addresses, such as fields and electricity substations. ITB was withdrawn in April 2019 and replaced by OS MasterMap Highways Network The Address layers were withdrawn in about 2016 with the information now being available in the AddressBase products - so as of 2020, MasterMap consists of Topography and Imagery. Pricing of licenses to ''OS MasterMap'' data depends on the total area requested, the layers licensed, the number of TOIDs in the layers, and the period in years of the data usage. ''OS MasterMap'' can be used to generate maps for a vast array of purposes and maps can be printed from ''OS MasterMap'' data with detail equivalent to a traditional 1:1250 scale paper map. Ordnance Survey states that thanks to continuous review, ''OS MasterMap'' data is never more than six months out of date. The scale and detail of this mapping project is unique. By 2009, around 440 million TOIDs had been assigned, and the database stood at 600 gigabytes in size. As of March 2011, OS claims 450 million TOIDs. As of 2005, ''OS MasterMap'' was at version 6; 2010's version 8 includes provision for Urban Paths (an extension of the "integrated transport network" layer) and pre-build address layer. All these versions have a similar Geography Markup Language, GML schema.


Business mapping

Ordnance Survey produces a wide variety of different products aimed at business users, such as utility companies and local authorities. The data is supplied by Ordnance Survey on optical media or increasingly, via the Internet. Products can be downloaded via FTP or accessed 'on demand' via a web browser. Organisations using Ordnance Survey data have to purchase a licence to do so. Some of the main products are: ; ''OS MasterMap'' : Ordnance Survey's most detailed mapping showing individual buildings and other features in a Vector graphics, vector format. Every real-world object is assigned a unique reference number (TOID) that allows customers to add this reference to their own databases. ''OS MasterMap'' consists of several so-called "layers" such as the aerial imagery, transport and postcode. The principal layer is the topographic layer. ; ''OS VectorMap Local'' : A customisable vector product at 1:10,000 scale. ; ''Meridian 2'', ''Strategi'' : Mid-scale mapping in vector format. ; ''Boundary-Line'' : Mapping showing administrative boundaries such as counties, parishes and Wards and electoral divisions of the United Kingdom, electoral wards. ; ''Raster versions of leisure maps'' : 1:10,000, 1:25,000, 1:50,000, 1:250,000 scale raster


Leisure maps

OS's range of leisure maps are published in a variety of scales: ; ''Tour'' : One-sheet maps covering a generally county-sized area, showing major and most minor roads and containing tourist information and selected footpaths. ''Tour'' maps are generally produced from enlargements of 1:250,000 mapping. Several larger scale town maps are provided on each sheet for major settlement centres. The maps have sky-blue covers and there are eight sheets in the series. Scales vary: ; ''OS Landranger'' : The "general purpose" map. They have pink covers; 204 sheets cover the whole of Great Britain and the
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Isle of Man
. The map shows all footpaths and the format is similar to the ''Explorer'' maps, but with less detail. ; ''OS Landranger Active'' : Select ''OS Landranger'' maps available in a plastic-Lamination, laminated waterproof version, similar to the ''OS Explorer Active'' range. , 25 of the 204 ''Landranger'' maps were available as ''OS Landranger Active'' maps. ; ''OS Explorer'', : Specifically designed for walkers and cyclists. They have orange covers, and contain 403 sheets covering the whole of Great Britain (the Isle of Man is excluded from this series). These are the most detailed leisure maps that Ordnance Survey publish and cover all types of footpaths and most details of the countryside for easy navigation. The ''OL'' branded sheets within the Explorer series show areas of greater interest (such as the Lake District, the Black Mountains, Wales, Black Mountains, etc.) with an enlarged area coverage. They appear identical to the ordinary ''Explorer'' maps, except for the numbering and a little yellow mark on the corner (a relic of the old ''Outdoor Leisure'' series). The ''OS Explorer'' maps, together with the former ''Outdoor Leisure'' series, superseded the numerous green-covered ''Pathfinder'' maps. In May 2015 Ordnance Survey announced that the new release of OL series maps would come with a mobile download version, available through a dedicated app on Android (operating system), Android and iOS devices. It is expected that this will be rolled out to all the Explorer and Landranger series over time. ; ''OS Explorer Active'' : ''OS Explorer'' and ''Outdoor Leisure'' maps in a plastic-laminated waterproof version. ; ''Activity Maps'' : An experimental range of maps designed to support specific activities. The four map packs currently published are ''Off-Road Cycling Hampshire'' North, South, East and West. Each map pack contains 12 cycle routes printed on individual map sheets on waterproof paper. While they are based on the 1:25,000 scale maps, the scales have been adjusted so each route fits on a single A4 sheet. Until 2010, OS also produced the following: ; ''Route'' : A double-sided map designed for long-distance road users, covering the whole of Great Britain. ; ''Road'' : A series of eight sheets covering Great Britain, designed for road users. These, along with fifteen ''Tour'' maps, were discontinued during January 2010 as part of a drive for cost-efficiency. The ''Road'' series was reintroduced in September 2016.


App development

In 2013, Ordnance Survey released its first official app, OS MapFinder (still available, but no longer maintained), and has since added three more apps. In 2021, OS Maps added coverage in Australia. ; ''OS Maps'' : Available on iOS and Android, the free to download app allows users to access maps direct to their devices, plan and record routes and share routes with others. Users can subscribe and download OS Landranger and OS Explorer high-resolution maps in 660dpi quality and use them without incurring roaming charges as maps are stored on the device and can be used offline – without WiFi or mobile signal. ; ''OS Maps Web'': Available as a web page – it allows users to access maps from the web using modern web browsers, planning of custom routes and printing of maps is possible similarly to what the mobile applications can do ; ''OS Locate'' : Launched in February 2014 and available on iOS and Android, the free app is a fast and highly accurate means of pinpointing a users exact location and displays grid reference, latitude, longitude and altitude. OS Locate does not need a mobile signal to function, so the inbuilt GPS system in a device can be relied upon.


Custom products

Ordnance Survey also offers ''OS Custom Made'', a print-on-demand service based on digital raster data that allows a customer to specify the area of the map or maps desired. Two scales are offered1:50,000 (equivalent to 40 km by 40 km) or 1:25,000 (20 km by 20 km)and the maps may be produced either folded or flat for framing or wall mounting. Customers may provide their own titles and cover images for folded maps. Ordnance Survey also produces more detailed custom mapping to order, at 1:1,250 or 1:500 (''Siteplan''), from its large-scale digital data. Custom scales may also be produced from the enlargement or reduction of the existing scales.


Educational mapping

Ordnance Survey supplies reproductions of its maps from the early 1970s to the 1990s for educational use. These are widely seen in schools both in Britain and in Changes in British sovereignty, former British colonies, either as stand-alone geographic aids or as part of geography textbooks or workbooks. During the 2000s, in an attempt to increase schoolchildren's awareness of maps, Ordnance Survey offered a free ''OS Explorer Map'' to every 11-year-old in Primary education#United Kingdom, UK primary education. By the end of 2010, when the scheme closed, over 6 million maps had been given away. The scheme was replaced by free access to th
Digimap for Schools
service provided by EDINA for eligible schools. With the trend away from paper products towards geographical information systems (GISs), Ordnance Survey has been looking into ways of ensuring schoolchildren are made aware of the benefits of GISs and has launched "MapZone", an interactive child-orientated website featuring learning resources and map-related games. Ordnance Survey publishes a quarterly journal, principally for geography teachers, called ''Mapping News''.


Derivative and licensed products

One series of historic maps, published by Cassini Publishing Ltd, is a reprint of the Ordnance Survey first series from the mid-19th century but using the ''OS Landranger'' Map projection, projection at 1:50,000 and given 1 km gridlines. This means that features from over 150 years ago fit almost exactly over their modern equivalents and modern grid references can be given to old features. The digitisation of the data has allowed Ordnance Survey to sell maps electronically. Several companies are now licensed to produce the popular scales (1:50,000 and 1:25,000) and their own derived datasets of the map on CD/DVD or to make them available online for download. The buyer typically has the right to view the maps on a PC, a laptop, and a pocket PC/smartphone, and to print off any number of copies. The accompanying software is GPS-aware, and the maps are ready-calibrated. Thus, the user can quickly transfer the desired area from their PC to their laptop or smartphone, and go for a drive or walk with their position continually pinpointed on the screen. The individual map is more expensive than the equivalent paper version, but the price per square km falls rapidly with the size of coverage bought.


Free access to historic mapping

The National Library of Scotland provides free access to OS mapping from 1840 to 1970, in a variety of scales from 1:1056 "five foot" maps of London to 1:625,000 "ten mile" national planning maps.


History of 1:63360 and 1:50000 map publications


Cartography

The Ordnance Survey's original maps were made by triangulation. For the second survey, in 1934, this process was used again and resulted in the building of many triangulation pillars (trig points): short (c. 4 feet/1.2 m high), usually square, concrete or stone pillars at prominent locations such as hill tops. Their precise locations were determined by triangulation, and the details in between were then filled in with less precise methods. Modern Ordnance Survey maps are largely based on orthophoto, orthorectified aerial photography, aerial photographs, but large numbers of the triangulation pillars remain, many of them adopted by private land owners. Ordnance Survey still has a team of surveyors across Great Britain who visit in person and survey areas that cannot be surveyed using photogrammetric methods (such as land obscured by vegetation) and there is an aim of ensuring that any major feature (such as a new motorway or large housing development) is surveyed within six months of being built. While original survey methods were largely manual, the current surveying task is simplified by the use of Global Positioning System, GPS technology, allowing the most precise surveying standards yet. Ordnance Survey is responsible for a UK-wide network of GPS stations known as "OS Net". These are used for surveying and other organisations can purchase the right to utilise the network for their own uses. Ordnance Survey still maintains a set of master Geodesy, geodetic reference points to tie the Ordnance Survey Geodetic datum, geographic datum points to modern measurement systems such as GPS. Ordnance Survey maps of Great Britain use the
Ordnance Survey National Grid The Ordnance Survey National Grid reference system (also known as British National Grid (BNG)) is a system of geographic grid reference A projected coordinate system, also known as a projected coordinate reference system, a planar coordin ...

Ordnance Survey National Grid
rather than Geographic coordinate system#Geographic latitude and longitude, latitude and longitude to indicate position. The Grid is known technically as OSGB36 (Ordnance Survey Great Britain 1936) and was introduced after the 1936–1953 retriangulation. Ordnance Survey's CartoDesign team performs a key role in the organisation, as the authority for cartographic design and development, and engages with internal and external audiences to promote and communicate the value of cartography. They work on a broad range of projects and are responsible for styling all new products and services.


Research

For several decades Ordnance Survey has had a research department that is active in several areas of geographical information science, including: * Spatial cognition * Cartographic generalization, Map generalisation * Spatial data modelling * Remote sensing and analysis of remotely sensed data * Semantics and Ontology (information science), ontologies Ordnance Survey actively supports the academic research community through its external research and university liaison team. The research department actively supports MSc and PhD students as well as engaging in collaborative research. Most Ordnance Survey products are available to UK universities that have signed up to the Digimap agreement and data is also made available for research purposes that advances Ordnance Survey's own research agenda. More information can be found a
Ordnance Survey Research


Data access and criticisms

Ordnance Survey has been subject to criticism. Most centres on the point that Ordnance Survey possesses a virtual government monopoly on geographic data in the UK, but, although a government agency, it has been required to act as a trading fund (i.e. a commercial entity) from 1999 to 2015. This meant that it is supposed to be entirely self-funded from the commercial sale of its data and derived products whilst at the same time the public supplier of geographical information. In 1985, the Committee of Enquiry into the Handling of Geographic Information was set up to "advise the Secretary of State for the Environment within two years on the future handling of geographic information in the UK, taking account of modern developments in information technology and market needs". The committee's final report, published in 1987 under the name of its chairman Roger Chorley, 2nd Baron Chorley, Roger Chorley, stressed the importance of accessible geographic information to the UK and recommended a loosening of policies on distribution and cost recovery. In 2007 Ordnance Survey were criticised for contracting the public relations company Mandate Communications to understand the dynamics of the Open Data in the United Kingdom, free data movement and discover which politicians and advisers continued to support their current policies.


''OS OpenData''

In response to the feedback from a consultation ''Policy options for geographic information from Ordnance Survey'' the government announced that a package of Ordnance Survey data sets would be released for free use and re-use. On 1 April 2010 Ordnance Survey released the brand
OS OpenData
' under an attribution-only license compatible with Creative Commons license, CC-BY. Various groups and individuals had campaigned for this release of data, but some were disappointed when some of the profitable datasets, including the leisure 1:50,000 scale and 1:25,000 scale mapping, as well as the low scale Mastermap were not included. These were withheld with the counter-argument that if licensees do not pay for OS data collection then the government would have to be willing to foot a £30 million per annum bill to obtain the future economic benefit of sharing the mapping. In mid-2013 Ordnance Survey described an "enhanced" Linked data, linked-data service with a SPARQL 1.1-compliant endpoint and bulk-download options. In June 2018, following the recommendations of the Geospatial Commission, part of the Cabinet Office, it was announced that parts of OS Mastermap would be released under the Open Government Licence. These would include: * property extents created from OS MasterMap Topography Layer * TOIDs from OS MasterMap Topography Layer, by integration into OpenMap Local Other data would be made available free up to small businesses (under a transaction threshold) * OS MasterMap Topography Layer, including building heights and functional sites * OS MasterMap Greenspace Layer * OS MasterMap Highways Network * OS MasterMap Water Network Layer * OS Detailed Path Network These are available through APIs on th
OS Data Hub


Historical material

Ordnance Survey historical works are generally available, as the agency is covered by Crown Copyright: works more than fifty years old, including historic surveys of Britain and Ireland and much of the New Popular Edition, are in the public domain. However, finding suitable originals remains an issue as Ordnance Survey does not provide historical mapping on 'free' terms, instead marketing commercially 'enhanced' reproductions in partnership with companies including GroundSure and Landmark. The National Library of Scotland has been developing its archive to make Ordnance Survey maps for all of Great Britain more easily available through their website. Wikimedia has complete sets of scans of the Old/First series one-inch maps of England and Wales; of the Old/First series one-inch maps of Scotland; of the Seventh Series One-inch maps of Great Britain (1952-1967); of the Third Edition quarter-inch maps of England and Wales; and of the Fifth Series quarter-inch maps of Great Britain. These sets are complete in the sense of including at least one copy of each of the sheets in the series, not in the sense of including all revision levels. The (GB) Ordnance Survey's approach can be contrasted with, for example, that of Ordnance Survey Ireland. OSI holds copyright over its mapping (and over digital copies of the public domain historical mapping), but all its maps (historic and current) are available free to view on their website (but not to reuse without a license).


See also

* Admiralty chart * Alastair Macdonald (surveyor), Alastair Macdonald, Director of Surveys and Production at Ordnance Survey 1982–1992 * Benchmark (surveying) * Cartography * Directors of the Ordnance Survey * Geoinformatics * Grid reference ** Great Trigonometric Survey ** Irish national grid reference system **
Ordnance Survey National Grid The Ordnance Survey National Grid reference system (also known as British National Grid (BNG)) is a system of geographic grid reference A projected coordinate system, also known as a projected coordinate reference system, a planar coordin ...

Ordnance Survey National Grid
* Hydrography ** Hydrographic survey ** United Kingdom Hydrographic Office * International Map of the World * Geographers' A-Z Map Company, principal partner of the OS * Martin Hotine, founder of the Directorate of Overseas Surveys * (List of) National mapping agency, national mapping agencies * Ordnance datum (sea level) * Ordnance Survey International * Ordnance Survey Ireland *
Ordnance Survey of Northern Ireland Ordnance may refer to: Military and defense * Ordnance items in military logistics Military logistics is the discipline of planning and carrying out the movement, supply, and maintenance of military forces. In its most comprehensive sense, it is ...
* Romer, a device for accurate reading of grid references from a map


References


Notes


Citations


Sources

* * * * * * * * * * * *


External links

* {{authority control Ordnance Survey, 1791 establishments in Great Britain Cartography organizations Department for Business, Energy and Industrial Strategy Geodesy organizations Geographical databases in the United Kingdom Geography of the United Kingdom Geography organizations Government databases in the United Kingdom Government-owned companies of the United Kingdom Surveying organizations Maps of the United Kingdom National mapping agencies Organisations based in Southampton Organizations established in 1791 Geographic data and information organisations in the United Kingdom Surveying of the United Kingdom