Extracting trends (III)

Following again on from my previous two posts (1)(2), I have been experimenting further with constructing trend surfaces, this time for specific sub-sets of my downloaded AIP data for evaluations and post-determination / research results from 1990 to 2010.

First, I removed all of the data for investigations that had no results in terms of dated features, which results in a very similar trend surface to that for all of the data including investigations with no substantive positive evidence:

1 AIP_trend_noNegEvid
12th power trend surface for AIP data (excluding investigations with no positive results)

Then I constructed trend surfaces for the same data but filtered down to investigations producing results for each of EngLaId’s four main broad time periods:

2 AIP_trend_BA
12th power trend surface for AIP data (Bronze Age)
3 AIP_trend_IA
12th power trend surface for AIP data (Iron Age)
4 AIP_trend_RO
12th power trend surface for AIP data (Roman)
5 AIP_trend_EM
12th power trend surface for AIP data (early medieval)

These results all look quite interesting to me, especially as they all vary quite significantly from the overall trend for all periods (albeit this is less the case for the Roman data).  The Bronze Age data shows a very clear bias towards an arc across south-eastern England from Dorset through to Kent and up into parts of East Anglia (the dry bits essentially), with the exception of the South Downs and the Weald.  The Iron Age is very strongly biased towards the counties north of London up to Cambridgeshire, across to north-east Kent and along the south coast.  There is also more of a northern trend than in the Bronze Age, with quite a significant peak in East Yorkshire.  The Roman data is distinctly biased towards London, Kent, the south coast, East Yorkshire and the Severn estuary region.  There is a surprising lack of any significant peak in the Tyneside area, considering the significant peak there in the data for all periods and the presence of Hadrian’s Wall.  For the early medieval, there is a very clear bias towards eastern England around the Fens and towards Kent.

I particularly like these results as they largely differ so significantly from the overall trend for all periods, which suggests that these patterns are more likely to be due to genuine distributions of underlying archaeological data, not just due to patterns of modern fieldwork (albeit this will still remain a very significant factor).  I am not sure any of the results are particularly surprising, interpretively, but they do confirm for me that we can extract spatial patterning from AIP data that is not just wholly biased towards areas of significant modern development.

Chris Green

Author: Chris Green

Postdoctoral Researcher (GIS)

4 thoughts on “Extracting trends (III)”

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