Sunday 9 February 2014

Everyone loves a map but where did they come from?


An introduction to Scottish maps and map making

Most good journeys start with a map1, but first we should consider where the maps came from and what limits there are to using them to interpret the landscape of today.
This introduction should not be considered as exhaustive or definitive but consider it a source of discussion, enlightenment or an entertaining distraction.
Early Maps
The earliest2 map of Scotland is from a book called Geography by the polymath Claudius Ptolemy (c. AD 90 – c. AD 168) who was a Greek-Roman citizen of Egypt. His book discusses the geographic knowledge of the Greco-Roman world. Unfortunately there are no surviving contemporary copies of the book and the map illustrated here is from a 17th century copy (Illustration 1).

Illustration 1: The Ptolemy map is the earliest known depiction of Scotland in a map.




The main thing is that it is recognisable as what we would consider to be a map. Although not great on detail or accuracy compared to the maps of today, he showed great skill in tackling the problem of projecting the curved world on to a flat surface. This attempt at portraying the world with a degree of geographical accuracy was not continued in the coming years.
Medieval maps.
Early maps were the creation in varying degrees of tradesmen as well as craftsmen, and of artists as much as scientific surveyors. Medieval land surveying was concerned primarily with written rather than graphic description and with valuation rather than exact measurement3. Compare the work of Ptoleomy with those of much later and you will see a more unscientific representation of the world (Illustration 2).




Illustration 2: World map c1265. This map is one of the most important surviving examples of 13th-century map-making. Jerusalem is in the centre of the map, and the whole world is looked upon by Christ who is attended by angels. This shows that medieval people looked at geography in relation to the Bible and to earth’s creation by God. But the map also shows an interest in local places: you can see the British Isles, and the rivers Thames and Severn. London is marked with a gold dot. The map was not intended, like a modern atlas, to guide someone in their travels, but to show important places in an overall prospect. http://www.bl.uk/learning/timeline/item99816.html





One of the most realistic maps of the medieval period was by a Saint Albans monk called Matthew Paris c1250, he has the basic shape of Britain correct but with Scotland shown as an island (Illustration 3). He was perhaps the first medieval mapmaker to try to portray the actual physical appearance of the country rather than just represent the relationship between places in simple diagrams.

Illustration 3: Matthew Paris map of Britain, c.1250 Copyright © The British Library Board




By 1560 the Italians had made quite a recognisable map of Scotland (Illustration 4).


Illustration 4: Italian Map of Scotland 1560





County maps.
With one or two exceptions, there are no separate maps of the regions of Britain before Elizabethan times but from Elizabethan to mid Victorian times the county was always the basic unit of regional mapping4. The county maps have there own set of problems when they are used as an aid to historical detection. J B Harley states:
'County maps can seldom (if ever) be regarded as a definitive or completely up to date record of topography for the time of their production.'5.
The cost of the survey would have to be borne by interested parties such as the gentry and this, plus the interests of the surveyor, could influence what got included in the map and what got left out.
Since the maps of the time were often a commercial venture, there was a bias towards well populated areas which were mapped more often and in more detail than remoter areas. In fact the act of surveying and map making was an expensive business and many of the map makers ran into financial difficulties. This can lead to difficulties with dating maps of this period since it was cheaper to re-engrave an earlier map with little or no resurveying done but give the publishing date not the surveying date.
However, the county maps produced by private surveyors between 1760 and 1840 are the most detailed maps of rural areas of Scotland up until the end of the 19th century6.
County maps showed perhaps for the last time, a degree of artistry (Illustration 5) and ornamentation that is not present in the maps produced today. These county maps have now found a new use as an object of art and are often seen hanging on the wall of many a country pub.


Illustration 5: William Forrest Map of Haddingtonshire 1799




Uniformity and Precision
Accurate surveying of the country required systems of very large triangles, called triangulation networks. In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly. A mesh of triangles at the largest appropriate scale is established first. Points inside the triangles can all then be accurately located with reference to it.
Britain could not have a complete accurate survey of the country without a full triangulation and the cost of this could not be provided for by private subscribers, but would need to be funded by the government.
The need for uniform, accurate maps, of the whole kingdom related everywhere to one national triangulated framework, was brought into sharp focus by the seemingly unconnected events of the Jacobite Rebellion of the 1700s.
Dukes and military maps
The battle of Culloden in April 1746 highlighted the need for accurate maps. The best map available at the time was of a scale of 1 inch to 13.5 miles or 1:855360, which was too small for the detail needed by military commanders7.
Lieutenant Colonel David Watson put forward the proposal for a survey to the Duke of Cumberland who gained authority for it from his father George II. The King was keen to provide any assistance with the pacification of the highlands.
The responsibility for the military survey of Scotland was delegated to William Roy and was completed by 1755. Roy then promoted the idea of a complete triangulation of Britain as a basis for more accurate mapping.
Roy died in 1790 and it took the Duke of Richmond to champion the cause of the complete triangulation. The Duke was the Master General of His Majesty's Ordnance and it was he who initiated the Trigonometrical Survey which was later to become known as the Ordnance Survey. Ordnance is the department responsible for military stores and equipment, hence the rather odd title of the British National Survey Organisation8.

Ordnance Survey
The primary triangulation of Scotland started in 1814 but it wasn't until 1859 that most of the Scottish lowlands were complete. Although the initial mapping of England and Wales had been undertaken at the one-inch scale,the growing need for detailed maps for land valuation, registration and conveyancing, agricultural improvement, mineral development, railways, together with the facts of urban expansion, lent advantage to the more detailed mapping at 24" to 26" to the mile scales. However, the successful mapping of Ireland at the six-inch scale had lead to the decision to follow this in the 1840s in Lancashire, Yorkshire, and Scotland9.
However accurate maps might be in trigonometrical terms, they were valueless as records of property ownership and guides to taxation without agreed names. Where a place may have more than one name or many spellings, the surveyors would consult an authority in the local populous. The 'Authority' of an individual usually followed a class or professional hierarchy. Here is an example of the detailed advice given to surveyors regarding authority and names:
'For the name of a house, farm, park or wood, or other part of an estate the owner is the best authority. For names generally the following are the best individual authorities and should be taken in the order given: Owners of property; estate agents; clergymen, postmasters and schoolmasters, if they have been some time in the district; rate collectors; borough and county surveyors; gentlemen residing in the district; Local Government Board Orders; local histories; good directories. Respectable inhabitants of some position should be consulted. Small farmers and cottagers are not to be depended on, even for the names of the places they occupy, especially as to the spelling. But a well-educated and independent occupier is, of course, a good authority'10.
Map Production
The six-inch maps of Scotland were engraved on special hammered copper, 1/10th inch thick and measuring 26.5 by 38.5 inches in extent. After scoring the sheet lines and marking the position of trigonometrical stations with fine dots, the plates were covered with wax, the outlines copied from tracings, and then cut into the plate in reverse using a graver or burin. Map engraving was a highly specialised process, and took a long time with high quality results. In time the engravers became the highest paid branch of the Survey.
A copper plate could only make about 500 impressions before re-engraving or copying by electrotyping was required.
Ordnance Survey Today
The laborious task of re-triangulating Britain was undertaken in the mid 20th century using a new set of triangulation pillars and up to date theodolites. However this technology was responsible for laying down a firm foundation on which to build a more accurate map of Britain it was made redundant with the revolution in map making that came with digital age.
The modern Ordnance Survey map is produced by state-of-the-art satellite technology and theodolite 'total stations' with lasers to measure distances. The national network of around 100 base stations constantly transmit their GPS-observed positions to a central processing hub11. The survey control network of 'trig' pillars was accurate to 20 metres over the entire length of Great Britain. Today the receivers that make up the OS Net network are coordinated to an accuracy of just 3 mm over the same area12.
Information gathered by ground staff is complemented by an intensive programme of aerial photography which is viewed in 3D.The resulting high-definition images, which show detail as sharp as the pattern of road markings, can then be overlaid with existing map data to check where features have changed so that instant updates can be recorded.
The new information from both ground and air surveys is added to the OS MasterMap database. The result is a definitive digital picture of Britain’s geography and the largest database of its kind anywhere in the world, made up of almost half a billion features.
So now we have the most accurate maps ever produced, and this introduction may read simply as a history of improvements in accuracy over time, ending up with present day maps that are best of all. However, does this mean that the more accurate maps are 'better' maps? Perhaps for certain uses they indeed are but they don't tell us as much about the landscape of the past and the peoples relationship to it, as the old maps do. However what they do provide is an accurate (for today's standard) baseline from which to measure changes in the future or perhaps they will be dismissed by the people of the future as artistic but sort of infantile compared to the wonders of the future.

References


1All of the maps come from the National Library of Scotland unless otherwise stated.
2http://www.bbc.co.uk/news/uk-scotland-15008220
3Harley,J. B., 1972. Maps for the Local Historian. ISBN 719908345: page 6.
4Harley,J. B., 1972. Maps for the Local Historian. ISBN 719908345: page 67.
5Harley,J. B., 1972. Maps for the Local Historian. ISBN 719908345: page 72.
7 Dickinson, G. B., 1969. Maps and Air Photographs. ISBN 71315425x, Page 4.
8Dickinson, G. B., 1969. Maps and Air Photographs. ISBN 71315425x,Page 45.
9Fleet, C. and Withers, C.,Ordnance Survey Maps - Six-inch 1st edition, Scotland, 1843-1882: A Scottish paper landscape. National Library of Scotland.(http://maps.nls.uk/os/6inch/os_info1.html).
10Seymour, W A (ed.) 1980.A history of the Ordnance Survey, Page 180.

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