Grids & Datums UNITED KINGDOM By Clifford J. Mugnier, C.P., C.M.S.

gland and agreed to join as Great naissance in 1819. In 1824, Parliament or- “OS was founded in 1791 by Britain in 1707 and with Ireland in 1801. The dered Colby and most of his staff to Ireland, the Master General of Ordnance present name of Great Britain and Northern to produce a detailed six-inch to the mile [equivalent to the Minister of Ireland was adopted in 1927. The area of valuation survey. Colby designed specialist Defense today], Charles Lennox, Great Britain is slightly smaller than Oregon; measuring equipment, established system- the kingdom has a 12,429 km coastline and atic collection of place names, and reorga- Duke of Richmond. His Grace the lowest point is Fenland (-4 m), the high- nized the map-making process to produce had been an outspoken sup- est point is Ben Nevis (1,343 m). Great Brit- clear, accurate plans. But Colby the perfec- porter of the American colonists ain is only 35 km from France and is linked by tionist also traveled with his men, helped to in the House of Lords. In the “Chunnel.” Because of the heavily in- build camps, and arranged mountaintop feasts December 1775 he declared dented coastline, no location in the country with huge plum puddings at the end of each is more than 125 km from tidal waters! season. that the resistance of the Thanks to the web site of the Ordnance “Soon after the first Irish maps began to colonists was “neither treason Survey, “England was squeezed between appear in the mid-1830s, the demands of nor rebellion, but it is perfectly rebellion in Scotland and war with France the Tithe Commutation Act provoked calls justifiable in every possible when King George II commissioned a mili- for similar six-inch surveys in England and tary survey of the in 1746. Wales. The government prevaricated but, political and moral sense.” Yet The job fell to William Roy, a far-sighted by then, there was a new power in the land. less than 10 years later he was a young engineer who understood the strate- This was the era of railway mania and if the government minister – I think gic importance of accurate maps. Walk into one-inch map was unsuitable for calculating anywhere else in Europe he ’s Southampton headquar- tithes, it was virtually useless for the new ters and you’ll see Roy’s name engraved on breed of railway engineers. To make matters would have been executed or the curved glass entrance doors, yet his vi- worse, mapping of England and Scotland re- exiled! He was succeeded as sion of a national military survey wasn’t mained incomplete and, in 1840, the Trea- Master General by Lord implemented until after his death in 1790. sury agreed that the remaining areas should Cornwallis, who didn’t appear By then Europe was in turmoil, and there be surveyed at the six-inch scale. Now, sur- were real fears that the French Revolution veyors needed greater access than ever be- to have suffered any long-term might sweep across political damage by that unfor- the English Channel. tunate incident at Yorktown. An Realizing the danger, Major General William Roy once wrote, “On early Director General of OS, the government or- one occasion he (Ramsden) attended at William Mudge, had served on dered its defense Buckingham Palace precisely as he supposed ministry – the Board Cornwallis’s staff in the southern of Ordnance – to be- at the time named in the Royal mandate. The colonies.” gin a survey of King remarked that he was punctual as to the — Russell Fox, Ordnance Survey England’s vulnerable day and hour, while late by a whole year!” southern coasts. In June 1791, the Board The United Kingdom includes England, Scot- purchased a huge new Ramsden theodolite, fore; and so, in 1841, the Ordnance Survey land, Wales, and Northern Ireland. The latter and surveyors began mapping southern Brit- Act gave them a legal right to ‘enter into was included in a previous column on the ain from a baseline that Roy himself had and upon any land’ for survey purposes. A entire island of Ireland (PE&RS, March 1999). measured several years earlier. few months later Ordnance Survey’s Evidence from pre-Roman times includes “The first one-inch map of Kent was pub- cramped Tower of London offices were at Neolithic mound-tombs and henge monu- lished in 1801, and a similar map of Essex the centre of a national catastrophe when ments as well as Bronze Age Beaker culture followed – just as Nelson’s victory at Trafalgar fire swept through the Grand Storehouse, tools, graves, and the famous Stonehenge made invasion less likely! Within twenty threatening to engulf the Crown Jewels in monument. Brythonic-speaking Celtic years about a third of England and Wales had the Martin Tower. Miraculously, the Jewels peoples arrived during migrations of the first been mapped at the one-inch scale. If that were saved, and most of Ordnance Survey’s millennium B.C., according to Webster’s seems slow in these days of aerial surveys records and instruments were also carried Geographical Dictionary. England has existed and global positioning, spare a thought for to safety. But the blaze highlighted the as a unified entity since the 10th century. Major Thomas Colby – later Ordnance Survey’s desperate need for more office The union between England and Wales was Survey’s longest serving Director General – space, and prompted a move to Southampton. begun in 1284 and formalized in 1536. En- who walked 586 miles in 22 days on a recon- “The scene was now set for two decades

1092 October 2003 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING Grids & Datums of wrangling over scales. Throughout this now familiar concrete triangulation pillars mapping agency’s data now underpins up to period, Victorian reforming zeal was creat- on remote hilltops throughout Britain. Deep £136 billion-worth of economic activity in ing an acute need for accurate mapping. The foundations were dug by hand, and staff Britain – everything from crime-fighting and issue was settled piecemeal until, by 1863, dragged heavy loads of materials over iso- conservation to marketing and mobile scales of six inches and twenty-five inches lated terrain by lorry, packhorse and sheer phones.” to the mile had been approved for mountain brute force. The Davidson Committee’s final The original triangulation of Britain was and moorland, and rural areas respectively. report set Ordnance Survey on course for carried out between 1783 and 1853 and is The one-inch map was retained, and detailed the 21st century. The National Grid refer- known as the “Principal Triangulation.” Jesse plans at as much as ten feet to the mile ence system was introduced, using the Ramsden, a gifted but dilatory gentleman, were introduced for built-up areas. as its measurement. An experimental new built the theodolite where the overall size “By now, Major-General Sir 1:25,000 scale map was launched, leaving of the horizontal circle measured 3 feet in – perhaps Ordnance Survey’s most eccen- only the one-inch unscathed. It was almost diameter and was divided to a precision of a tric and egotistical Director General – was forty years before this popular map was su- tenth of an arc second! (That’s the same pre- midway through his twenty-one year term. perseded by the 1:50,000 scale series, first cision as the Wild Heerbrugg T-4 astronomi- James quickly saw how maps could be proposed by William Roy more than two cen- cal theodolite still manufactured as recently cheaply and quickly enlarged or reduced us- turies earlier. as the 1980s). Major General William Roy ing the new science of photography, and he “In 1939, war intervened once again. The once wrote, “On one occasion he (Ramsden) designed an elaborate glass studio at Royal Artillery was now responsible for its attended at Buckingham Palace precisely as Southampton for processing photographic own field surveys, but over a third of Ord- he supposed at the time named in the Royal plates. James planted his name on every- nance Survey’s civilian staff were called up, mandate. The King remarked that he was thing he touched, and later claimed to have and its printing presses were kept busy with punctual as to the day and hour, while late invented photo zincography, a photographic war production. It wasn’t a soft option. En- by a whole year!” The genius responsible for method of producing printing plates. In fact, emy bombing devastated Southampton in the final adjustment and computation of the the process had been developed by two of November 1940 and destroyed most of Ord- Principal Triangulation of 1783-1853 was his staff. By 1895 the twenty-five inch sur- nance Survey’s city centre offices. Staff were Colonel Alexander Ross Clarke who also vey was complete. dispersed to other buildings, and to tempo- computed the Clarke ellipsoids of 1858, 1866, “The twentieth century brought cyclists rary accommodation at Chessington. But the and 1880. The network selected by Clarke and motorists swarming onto the roads, and military appetite remained insatiable – the was an interlocking system of well-condi- the new Director General, Colonel Charles Normandy landings alone devoured 120 mil- tioned triangles. In 1967, the Ordnance Sur- Close, prepared to exploit this expanding lion maps! vey wrote, “This network was geometrically leisure market. But by now, the tide of his- “After the war, Ordnance Survey returned of great strength since it involved no fewer tory was sweeping Ordnance Survey back to Davidson’s agenda; the retriangulation was than 920 condition equations to find correc- to its roots. As Britain entered the First completed, and metric maps began to ap- tions to 1,554 observed directions subse- World War, surveyors, draughtsmen and pear along National Grid sheet lines. Aerial quently used to fix 218 points.” The One- printers from Ordnance Survey were posted survey helped speed up the new continu- Inch map series referred to a map scale of overseas. Working in appalling conditions ous revision strategy, and up-to-date draw- one inch equals one mile. The One-Inch Scot- alongside the troops, surveyors plotted the ing and printing techniques were introduced. tish Bonne projection (1852-1936) was based lines of trenches and, for the first time, aerial But the organization was still fragmented, on the Principal Triangulation and had a cen- photography was used to capture survey scattered across southern England in a bat- tral meridian λo = 4º W, a latitude of origin information. tered collection of worn-out buildings. All ϕo = 57º 30¢ N, a scale factor of unity, and “After the war, Sir Charles, as he now that changed in 1969, when Ordnance Sur- with no false Origin. The One-Inch English was, returned to his marketing strategy and vey moved to its present, purpose-built and Welsh Cassini projection (1919-1936) was appointed a professional artist to produce headquarters on the outskirts of also based on the Principal Triangulation and eye-catching covers for the one-inch maps. Southampton. Four years later, the first com- had a central meridian λo = 2º 41' 03.5620" W,

Ellis Martin’s classic designs boosted sales puterized large-scale maps appeared; the a latitude of origin ϕo = 53º 13' 17.2740" N, a to record levels, but the war had taken its digital age had begun. Ordnance Survey digi- scale factor of unity, and with no false Origin. toll; behind their bright new covers, the tized the last of some 230,000 maps in 1995, The counties of the United Kingdom were maps were increasingly out of date. In an making Britain the first country in the world based on local Cassini-Soldner projections that uncanny echo of the mid-nineteenth cen- to complete a programme of large-scale elec- had the typical scale factor equal to unity, no tury, a whole raft of new legislation brought tronic mapping. Computers have transformed false origin, and a single triangulation station demands for accurate, up-to-date mapping. the map-making process, and electronic data as the projection origin. System Ben Auler

“Matters came to a head in 1935, and the is now routinely available to customers (ϕo = 56º 48' 50.3889" N, λo = 4º 27' 49.7064" W) Davidson Committee was established to re- within 24 hours of being surveyed. The pub- served the counties Canna, Eigg, Muck, Rhum, view Ordnance Survey’s future. That same lic still knows Ordnance Survey for its com- Sanday, and Skye of the Inner Hebrides and year, a far-sighted new Director General, prehensive range of printed leisure maps, Inverness of Scotland. System Ben Cleuch

Major-General Malcolm MacLeod, launched yet electronic data now accounts for some (ϕo = 56º 11' 08.8438" N, λo = 3º 46' 05.2765" W) the retriangulation of Great Britain. Survey- 80% of Ordnance Survey’s turnover. Inde- served the counties Clackmannan and Perth ors began an Olympian task, building the pendent estimates show that the national continued on page 1094

PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING October 2003 1093 Grids & Datums

continued from page 1093 System Craigowl (ϕo = 56º 32' 52.4204" N, Isle of Wight, Leicester, Lincoln, Northamp-

of Scotland. System Ben Clibrig (1839) λo = 3º 00' 48.5178" W) served the county of ton, Nottingham, Oxford, Rutland, Warwick,

(ϕo = 58º 14' 07.8780" N, λo = 4º 24' 35.3627" W) Angus, Scotland. System Cruach-na-Sleagh Wiltshire, Worcester, and Stafford of En-

served the county of , Scotland. (ϕo = 56º 07' 08.9328" N, λo = 5º 43' 34.1145" W) gland. System Dunrig (1816, 1850) (ϕo

System Black Down (1797, 1840) (ϕ o served the counties Argyle, Arran, and Bute = 55º 47' 59.832" N, λo = 4º 32' 20.592" W)

= 50º 41' 10.3186" N, λo = 2º 32' 52.4856" W) of Scotland and Coll, Islay, Jura, Mull, and served the county of Peebleshire, Scotland.

served the counties Dorset and Somerset of Tiree of the Inner Hebrides. System Cryn-y- System Finlay Seat (ϕo = 57º 34' 42.2883" N,

England. System Bleasdale (ϕo = 53º 54' 55.351" N, Brain (1852, 1853) (ϕo = 53º 02' 16.8715" N, λo = 3º 14' 26.5655" W) served the county

λo = 2º 37' 20.752" W) served the county of λo = 3º 10' 22.2907" W) served the coun- of , Scotland. System Forest Hill (ϕo

Lancashire, England. System Brandon (1822) ties Denbighshire and Flintshire of Wales. = 54º 25' 30.700" N, λo = 2º 43' 41.593" W)

(ϕo = 52º 24' 19.820" N, λo = 0º 37' 21.040" W) System Danbury (Church) Spire (1844), served the county Westmorland of England.

served the counties Durham and (ϕo = 51º 42' 57.9220" N, λo = 0º 34' 32.9299" E) System Foula (1821) (ϕo = 60º 08' 26.2436" N,

Northumberland of England. System Broadfield served the counties Cambridgeshire and λo = 2º 05' 38.4808" W) served the counties

(ϕo = 55º 47' 59.8320" N, λo = 4º 32' 20.5920" W) Isle of Ely, Huntingdonshire, Soke of Pe- , and Zetland, Scotland. System Hart

served the county of Rentfrew, Scotland. Sys- terborough, Norfolk, and Suffolk of En- Fell (1816, 1847) (ϕo = 55º 24' 28.9742" N,

tem Brown Carrick (ϕo = 55º 24' 26.5714" N, gland. System Derrington Great Law (ϕo λo = 3º 24' 00.1634" W) served the county of

λo = 4º 42' 41.1291" W) served the counties = 55º 26' 08.9646" N, λo = 2º 26' 34.6838" W) Dumfries, Scotland. System Hensbarrow

Ayr, Wigtown, and Kirkcudbright, Scotland. served the county of Berwick, Scotland. (1790, 1843) (ϕo = 50º 22' 58.8532" N, λo

System The Buck (ϕo = 57º 17' 51.1940" N, System Ditchling (1793, 1845) (ϕ o = 4º 49' 05.1029" W) served the counties

λo = 2º 58' 32.0297" W) served the counties = 50º 54' 04.0149" N, λo = 0º 06' 21.7531" W) Cornwall, and Isles of Scilly, England. Sys-

Aberdeen, Banff, East , , served the county of Sussex, England. System tem Highgate (ϕo = 51º 41' N, λo = 4º 50' W)

Kincardine, Kinross, , and West Dunnet Head (1838) (ϕo = 58º 40' 10.1679" N, served the county of Pembroke, Wales. Sys-

Lothian of Scotland. System Cairn Glasher (ϕo λo = 3º 22' 13.4365" W) served the county of tem High Pike (ϕo = 54º 42' 19.3478" N, λo

= 57º 20' 22.8895" N, λo = 3º 50' 30.5116" W) , Scotland. System Dunnose = 3º 03' 26.5277" W) served the county of

served the county of , Scotland. System (1793, 1844) (ϕo = 50º 37' 03.7288" N, λo Cumberland, England. System Hollingbourne

Cleisham (1840) (ϕo = 57º 57' 50.6850" N, λo = 1º 11' 50.1015" W) served the counties (ϕo = 51º 16' 10.380" N, λo = 0º 39' 55.564" W) = 6º 48' 41.4340" W) served the Outer Hebrides. Berkshire, Buckingham, Derby, Hampshire, served the county of Kent, England. System

1094 October 2003 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING Grids & Datums

Lanark Church Spire (ϕo = 55º 40' 20.8037" N, the English Yard Belt Transverse Mercator Cliff Mugnier teaches Surveying, ,

λo = 3º 46' 19.8904" W) served the counties (mo = 0.9996, False Easting and False North- and Photogrammetry at Louisiana State Uni- , Lanark, , and Roxburgh of ing = 1,000,000 yds.) was short-lived and versity. He is the Chief of Geodesy at LSU’s Scotland. System Leith Hill Tower (1792, was replaced by a slightly different metric Center for GeoInformatics (Dept. of Civil and

1822, 1824) (ϕo = 51º 10' 32.8895" N, λo version in 1945 and it continues to be used. Environmental Engineering), and his geo- = 0º 22' 10.9797" W) served the county of The current system is the National Grid. Al- detic research is mainly in the subsidence of

Surrey, England. System Llangeinor (ϕo though the equations published appear to Louisiana and in Grids and Datums of the th = 51º 38' 26.6535" N, λo = 3º 34' 17.0360" W) be a Gauss-Krüger expansion to the 5 de- world. He is a Board-certified Photogram- served the counties Anglesey, Brecknock, rivative, they are cast as latitude differences metrist and Mapping Scientist (GIS/LIS), and Caernarvon, Cardigan, Carmarthen, from the False Northing latitude of true ori- he has extensive experience in the practice Glamorgan, Merioneth, Montgomery, and gin = 49° N. The central meridian = 2° W, and of Forensic Photogrammetry. Radnor of Wales and Hereford, Monmouth, the scale factor at the central meridian, com- Ô and Salop of England. System Nantwich monly mistaken for that of the TM Yard Grid The contents of this column reflect the views of the author, who is responsible for the facts and accuracy of Church Tower (ϕo = 53º 04' 00.3405" N, λo and the UTM Grid, is different in that by the data presented herein. The contents do not neces- sarily reflect the official views or policies of the Ameri- = 2º 31' 09.1414" W) served the county of definition, mo = 0.9996012717… ≡ Log10 m o Cheshire, England. System Rippon Tor (ϕ = 1.99982680, exactly. I would love to find can Society for Photogrammetry and Remote Sensing o and/or the Louisiana State University Center for GeoInfor- = 50º 33' 57.0563" N, λo = 3º 46' 12.0872" W) out where that number came from. The False matics (C4G). served the county of Devon, England. Sys- Easting is 400 km and the False Northing is – tem St. Paul’s (1848) (ϕo = 51º 28' 15.9830" N, 100 km.

λo = 0º 22' 47.6011" W) served the counties The Ordnance Survey seven-parameter of Bedford, Essex, Hertsford, London, and transformation from OSGB36 to WGS84 Middlesex, England. System Sandhope Heights modified to the standard American rotation

(ϕo = 55º 30' 10.253" N, λo = 3º 02' 31.092" W) convention used by the National Geodetic served the county of Selkirk, Scotland. System Survey (NGS) and by the National Imagery PE&RS BACK

Scour-na-Lapach (1846) (ϕo = 57º 22' 10.3858" N, and Mapping Agency is DX = +446.448 m, λ = 5º 03' 31.5613" W) served the counties of DY = –125.157 m, DZ = +542.060 m, scale = ISSUES SALE o –6 , Scotland. System South –20.4894´10 , RX = –0.1502", RY =–0.2470", Berule (1846) (ϕ = 54º 08' 57.5699" N, λ and R = –0.8421". “OSGB36 is an inhomoge- o o Z • ANY SET OF 12 ISSUES . $85 = 4º 40' 05.2960" W) served the Isle of Man, neous Terrestrial Reference Frame by mod- For USA Addresses

England. System York Minster (1846) (ϕo ern standards. Do not use this transforma- (postage included)

= 53º 57' 43.1879" N, λo = 1º 04' 49.7302" W) tion for applications requiring better than 5 Non-USA Addresses: served the counties York and Yorkshire, En- metre (sic) accuracy in the transformation Add $35 for postage. gland. step, either vertically or horizontally. Do not The re-triangulation of Great Britain was use it for points outside Britain.” The above • RESOURCE ‘2003 ...... $10 not based on a single origin point. How- transformation parameters were extracted • ANY 2003 ever, it was not based on any new length from A Guide to Coordinate Systems in Great SPECIAL ISSUE ...... $20 measurements, either. The overall size of Britain, a “pdf” file downloaded from the Ord- the network was constrained to agree with nance Survey’s web site, www.gps.gov.uk. • OTHER SINGLE ISSUES..... $7 the old 18th century Principal Triangulation Higher accuracy transformations are possible Add $3.00 postage per issue for Non-USA addresses. using the old coordinates of 11 primary sta- utilizing the free software available from the GST is charged to residents of Canada only tions adjusted by Clarke. Therefore, the Ordnance Survey in the form of OSTN02, a (GST #135123065). Tax is calculated at 7% x(subtotal + shipping charges). Ordnance Survey of Great Britain 1936 da- bi-linear interpolation package similar in con- tum (OSGB36) does not have a single origin cept to the NADCON package of the NGS. Availability: 1993 – 2002 point. The ellipsoid of reference is the Airy The British Geoid Model, OSGM02, is avail- Out of Print: 1830 where a = 6,377,563.396 m and b able and is free from the Ordnance Survey. January 1998, October & = 6,356,256.910 m. The overall size of the The stated vertical accuracy is 2 cm in main- December 1997; June 1996; OSGB36 is based on the measurement of a land UK and 4 cm for other areas. I hope that January 1994; March, July, single distance between two stations on other nations will follow the example of the August, September, & October 1993 in 1784 using 18-foot glass United Kingdom, Australia, Mexico, and the rods! The error incurred by using this scale United States in making critical national geo- TO ORDER, CONTACT: constraint yielded an error in the length of detic transformation models available at no ASPRS Distribution Center the entire country of only 20 meters! The charge to the public. I am indebted to Russell PO Box 305, Annapolis Junction, War Office Grid (1927-1950) was based on Fox, soon to retire from the Ordnance Sur- MD 20701-0305 the Cassini-Soldner projection and had a cen- vey, and to John W. Hager, now retired from 301-617-7812; 301-206-9789 (fax), [email protected] tral meridian λo = 1º 11' 50.1360" W, a lati- NIMA, for their patience over the years in tude of origin ϕo = 50º 37' 03.7480" N, a scale helping me to compile this mass of data on VISA, MasterCard, and factor of unity, False Easting = 500 km, and the UK. American Express are accepted. False Northing = 100 km. Introduced in 1931,

PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING October 2003 1095