Spatial Analysis of East AnglianAnglo Saxon ArchaeologyEdward Kemp

MSc Applied Geographical Information Systems Wednesday 7th September 2011

Presentation Structure

• Provide a background to the project.

• Explain the projects aims and objectives.

• Introduce the study area and data.

• Briefly explain the methods used.

• Share some results and conclusions.

• Did we achieve our objectives?

I mages from: Culture 24 www.culture24.org.uk

Background

• Dissertation topic inspired by a project from 2006 by John Naylor at Ashmolean Museum in Oxford

• Uses of an online database of archaeological finds found using metal detectors by members of the public

• Started in 1997 now has over 450,000 unique objects on the searchable database

• Run by the Portable Antiquities Scheme (PAS) in conjunction with the British Museum

Aims and Objectives• Explore archaeological data using spatial analysis techniques

• Explore distributions and patterns in the data with the aim of better understanding the development of Anglo Saxon East Anglia

• Assess the ‘productivity’ (level/type of activity) at previously identified archaeological sites using spatial analysis techniques and the PAS database

• Combine the results highlighting areas that could be investigated further through fieldwork or additional spatial analysis

Study Area

Preparing PAS Data

• Remove inconstancies in data• Remove any unclassified or incomplete items

• Object types assigned object groups• Finds assigned a period in Anglo Saxon history• Plotted using easting and northing grid references

id old_findID uniqueID Objecttype numdate1 numdate2primaryMaterial county parish

fourFigure easting northing

9237 NLM1126 0013EA1612201440 HARNESS FITTING 900 1066 Copper alloy SUFFOLK IPSWICH TM1744 617161 24458118478 SF3916 0013EA161240187E RING 410 720 Copper alloy SUFFOLK BLAXHALL TM3456 634000 25648018476 SF3914 0013EA161240187C STRAP FITTING 550 650 Copper alloy SUFFOLK BLAXHALL TM3456 634000 25648018691 SF4126 0013EA1612401953 STIRRUP 1000 1100 Copper alloy SUFFOLK BLAXHALL TM3456 634000 256480

Assigning Categories• Object groups and time periods were assigned to each item

• One of six object groups were assigned to each item:

• Clothing (buckle, hooked tag, sleeve clasp)• Coins (single coins, ingots)• Horse Items (stirrup, strap ends, bridle bit, harness mount)• Commercial and Household: (spoon, bowl, tweezers, hinge, gaming piece)• Jewellery (brooch, ring, bracelet, bead, armlet)• Pins (hair pin, linked pin)

• One of three time periods were also assigned to each item:

• Early: 400 – 600AD• Middle: 601 – 800AD• Late: 801 – 1066AD

• Each object group was broken down further by time period

Spatial Analysis Techniques• Average Nearest Neighbour:• Compare the distance between feature locations

• Global Morans I:• Compares the distance between feature values• Are similar or dissimilar values clustering

• Getis – Ord G* Hotspot Analysis:• Identifies whether features with high values or features with low values tend to

cluster together in a study area (forming ‘hot’ or ‘cold’ spots)

• All results were accompanied by a level of significance • Either 99%, 95% or 90%

• Use to accept or reject the null hypothesis• Points/ values were located as a result of a random process

Average Nearest Neighbour Findings

• Results gave an insight into the distribution of some object groups

• Overall finds showed less tendency to cluster over time

• Jewellery items showed the highest tendency to cluster

• Commercial and household items the least

• Both at a 99% confidence level

Global Morans I Findings

• Provided slightly different picture

• Finds again showed less tendency to cluster of time

• Clothing items showed the highest tendency to cluster at a 99% confidence level

• Commercial and household the least but with no confidence level attached

Getis –Ord G* Hotspot Analysis Findings

• No statistically significant cold spots were found

• Significant hotspots move around the study area over time

• The central area around the town of Hoxne seems to be important in the early – middle period

• The shift is then to the north and west of Norfolk

• Patterns in two of the maps indicate possible trade or communication routes – aid of underlying OS map

• One running from the VASLE site at Freckenham NE to Great Yarmouth and the other running SE to Felixstowe

All Coin Finds

Commercial and HouseholdLate PeriodFinds

Possible traderoutes

VASLE Productive Site (VPS) Analysis• Aim to assess the productivity of the 22 VPS using buffering and intersection

functions

• No specific definition of what a productive site is so buffer size and criteria were based on the 2006 project:

• 2.5 mile buffer chosen because of:• Dispersed settlement pattern• Increased distribution through trade as time goes on• Take into account disposal and accidental loss

• Productivity would be assessed by counting the number of object groups and time periods returning above average numbers of finds from the PAS dataset

• More than 4 out 6 object groups AND 2 out of 3 time periods and the VPS would be deemed productive throughout the Anglo Saxon period

22 VPS+ 2.5 mile buffers

VASLE Productive Site (VPS) Buffer Analysis Results

• 7 out of 22 sites were deemed to be productive as a result of the spatial analysis process

• Gave an indication as to when some sites developed

• Gave an indication of each sites primary function • Pin manufacture, tax and trade.

• Timings for the possible trade routes could be given, northern route earlier, southern route later

Conclusions – Did we achieve out objectives?

• Spatial analysis techniques can be successfully used in conjunction with complex archaeological data

• Patterns are revealed that can tell a story about a town or area

• These would not be apparent using purely visual inspection

• Each technique complimented each other

• The project has set the scene for future possible GIS projects

THANK YOU FOR LISTENING

ANY QUESTIONS?