Author

Dr Diane Palmer

Date

August 2007, Workshop October 2007

Project Type

Workshop for postgraduates

Subject

Criminology

Datasets

OS County Series, English Parishes

Related Subjects

GIS; History; Psychology; Literature

Sources: Digimap, UK Data Service Census Support (fomerly UKBORDERS), Charles Booth Online Archive

Key Words

Probability surfaces; Jack the Ripper

Dates/Editions: First Revision

Scale: 1:10,560 and 1:2,500

Publishing Institution

Interdisciplinary Centre of the Social Sciences (ICOSS)-University of Sheffield

Summary

The workshop will set out to consider the background to events of the Autumn of Terror in 1888 by studying the sociodemographics of Victorian London. A range of GIS techniques will then be employed to ascertain:

• Whether all the murders which occurred in the Whitechapel area of London during this period were the work of one killer only.

• If any of the suspects actually resided in a suitable location to commit the crime.

• Where the real killer lived.

Aims & Objectives

To teach the application of GIS techniques to both first-time and more experienced users. Techniques include:

• Zooming, panning, layer display via table of contents
• Labelling/Symbology/Thematic Mapping
• Use of Geodemographics
• Geographic Profiling
• Buffer
• Mean centre
• Probability Surfaces

Methodology

Additional data was first created. Point themes of location of victims and suspects were prepared by a combination of finding coordinates with streetmap.co.uk and searching the Ordnance survey historic maps.

Sociodemographics

Initially the students will be shown how to overlay Charles Booth’s Poverty Map of Whitechapel with victim locations. This simple process introduces the concept of geodemographics. It reveals that victims were found in areas which were either “Lower class, vicious, semi-criminal” or “Mixed, some comfortable, others poor”. Students are then shown how to create thematic maps from historic English Parishes data. These reveal that the population in Whitechapel actually fell 1871-1881, but the population density was high and the number of paupers compared to area was large (Maps 1 and 2).

How Many Killers?

Eleven women were murdered in Whitechapel between April 1988 and February 1891. They have all been considered to be ‘Ripper’ killings at some stage, although the ‘Canonical Five’ are undisputed victims. In an attempt to distinguish ‘Ripper’ casualties from other murders, students will be shown how to construct the Spatial-Temporal Moving Average in easy stages (repeated calculation of the mean centre over the series of events). This shows two mean areas of activity (Map 3), suggesting either at least two murderers or that the killer changed hunting ground. Map 3 also illustrates the results of Correlated Walk Analysis which allows the prediction of the next event in time, distance and direction. The predicted location of the sixth victim is in a very different area (off the top of the map) to where her body was actually found in Mitre Square.

Suspects

An investigation will be carried out to discover whether any of the suspects (from the subset who could be georeferenced) might have been the perpetrator. The technique of ‘donut’ ring buffers will be demonstrated to workshop participants. Map 4 indicates that 3 suspects (blue, green and dark blue buffers) lived in suitable places to commit the crimes. However, there are alibis and other reasons which make it impossible to construct a case against any of these men.

Residence of the Killer

Instructions to build up a simple probability surface of the killer’s home ground will be given. The following will be taken into account:

• distance to murder sites
• distance to pubs (for picking up streetwalkers, i.e. the target group)
• distance to St Botolphs (the red light district)
• distance to Goulston St (we know the Ripper was familiar with this location because Catherine Eddowes’ (murder number 6) apron was found there)
• Mary Kelly’s last walk (the last known movements of the final member of the ‘Canonical Five’).

Map 5 suggests two possible areas as likely ‘Ripper’ residences. Goulston Street was broad by standards of Victorian London and used as a cut-through. Dorset Street was notorious for vice, drunkenness and overcrowding and was a “No go” place for the nineteenth century constabulary. Interestingly, the peak area of the FBI’s more complex geoprofile focused on the locale around the equally notorious Flower and Dean Street and Thrawl Street (almost between the two locations identified in Map 5).

Results/Outcome

	Map 1: Location of ‘Ripper’ Victims compared to London Population Growth 1871-1881. Growth (pink) occurred in more outlying areas. Whitechapel experienced a fall.
	Map 2: Location of ‘Ripper’ Victims compared to Indoor Poor (resident in workhouse) 1881
	Map 3: Spatial-Temporal Moving Average and Correlated Walk Analysis of ‘Ripper’ Events
	Map 4: ‘Donut’ buffers of ‘Ripper’ suspects compared to location of victims.
	Map 5: Probability Surface of where the ‘Ripper’ lived

References & Acknowledgements

References

Alexander, Monica; Groff, Elizabeth and Hibdon, Laurie “An Automated System for the Identification and Prioritization of Rape Suspects”. Accessed: 6 August 2007. http://gis2.esri.com/library/userconf/proc97/proc97/to350/pap333/p333.htm

Metropolitan Police: http://www.met.police.uk/history/ripper.htm

Ryder, Stephen P. (Ed.). "Casebook: Jack the Ripper”. Accessed: 6 August 2007. http://www.casebook.org

Wikipedia: http://en.wikipedia.org/wiki/Jack_the_Ripper