Saturday, 17 April 2010

Medieval Fenlands GIS

[Note: see companion Post-medieval drainage of the Fens from same source
Update: see subsequent story with Ordnance Survey and 1SpatialOnline validation]

The recent release of UK Ordnance Survey OpenData opened the opportunity to post H.C. Darby's data from The Medieval Fenland and The Drainage of the Fens of East Anglia in the eastern UK. And parishes are the geographic unit that remained constant since the Middle Ages.

Thus historic geographic data from the Domesday census commissioned by William the Conqueror in 1087, can be compared in East Anglia with tax assessment data from Lay Subsidies of 1327 - 1332 and that of 1640 - 1641. Darby's magnum opus at King's College, Cambridge UK, was to compile Domesday data for England in 7 volumes. He also studied the Fenlands north of Cambridge as they evolved from medieval swamplands to drained fenlands before and after the Civil War.

At a relatively modest 200 pages, Darby's first book has an astonishing 25 map figures... and his second book has 310 pages and 35 map figures! OpenData now provides free infrastructure data such as counties and parishes, roads and rivers etc. in shape file format. It is therefore easy to derive a local subset for the counties of Norfolk, Cambridgeshire, Linclonshire, and the south end of Yorkshire. As parishes were the constant geographic unit, attributes were simply added to those shapefiles and filled with Darby's classifications. Data and details are available on request, as are metadata. Aso later data will be combined into a webmap.

Maps below illustrate how the economic wealth of East Anglia switched from the northern & southern uplands to the central lowlands after the Norman Conquest, and then changing little until after the Civil War.

(click on image to enlarge)

How does one compare economic wealth since early medival times in spatial and statistical terms? Darby reported two types of datasets: the Domesday census data for 1087, and the tax assessment data for 1327-1332 and 1640-1641 Lay Subsidies. Out of Domesday census, Darby tallies population, meadow extent and ploughteam numbers as economic indicators in an agrarian regime, before comprehensive monetary regimes were instituted - these were normalised on a per 1000 acres base and classified by parish for comparison across the three townships (no data for Norfolk or Suffolk reported, and Cambridgeshire was smaller then separated from Huntingtonshire). During the Middle ages monetary regimes were instituted as feodalism was gradually organised economically and centralised politically. Tax assessments are therefore good economic indicators for the four townhsips where data were reported in Darby's first book, and Cambridgeshire alone in his second book.

The map above classifies plough teams for 1087 and tax assessments for 1327-1332 all per 1000 acres by parish; as those for 1640-1641 are roughly double, the same classes are posted per 500 acres instead. This gives a geospatial reference at about 1000, 650 and 350 years ago! Darby used many more factors such as population, road and river access and commerce, plus governing and religious institutions to fill out the historical geography of the Fenlands. He concluded they were not a backwater as previously thought. They were in fact relatively prosperous first in the drylands and then in the fenlands, with little subsequent change in wealth distribution.

Couleur locale: The history of my neighbouring village Landbeach (next to Waterbeach, bottom centre of this map) goes back to William the Conqueror too. The moat still visible next to the village green, used to surround the manor. [The same exists in my village and Rampton in the opposite direction, and with castle forts in Iram Drove just to the north and Burwell further east] That manor had been awarded to two carpenters for services during the 1066 conquest! It had been held by the same family since then, until they drove crofters away in the 18th century to make way for grazing, as happened often in that era. That and other local conflicts spelled the demise of the manor, and courts turned it over to Cambridge University which sold it to the local council in the early 20th century. [Gleaned from a public sign post illustrating the manor grounds history.]