[DDI-users] DDI-driven on-line visualisation system

[Humphrey Southall]

I have done a couple of presentations at recent IASSIST meetings 
about the Vision of Britain web site and its implementation of the 
DDI Aggregate Data Extension to directly drive graphical 
visualisations of historical census and vital registration 
data.  However, although the site launched last year the parts that 
used the DDI did not.

I am therefore pleased to announce that the full Vision of Britain 
system is now live.  The site home page is at:

http://www.visionofbritain.org.uk

A direct interface to the DDI-based structures is available here:

http://www.visionofbritain.org.uk/data

An example of a particularly complex nCube getting presented, i.e. 
statistics from the Registrar General's Decennial Supplement for 
1861-70, is available here.  This nCube has three dimensions:  sex 
(two categories), age group (12 categories) and cause of death (25 categories):

http://www.visionofbritain.org.uk/data_cube_chart_page.jsp?data_theme=T_VITAL&data_cube=N_CoD_grouped&u_id=10001043&c_id=&add=Y

The graphs obviously contain rather too many causes of death, but we 
have mapped all five cause of death classifications used between 1851 
and 1910 to a single simplified classification designed by Graham 
Mooney of Johns Hopkins.  What is effectively a library of cause of 
death classifications can be explored here:

http://www.visionofbritain.org.uk/data/dds_entity_page.jsp?ent=VG_CoD

Once the mappings between the different variables had been set up, 
the new simplified nCube spanning the six decades for around 630 
Districts across England and Wales was populated by a single Oracle 
query, creating about 800,000 new derived values.  Here is the 
resulting data for a rural area near the Welsh border:

http://www.visionofbritain.org.uk/data_cube_chart_page.jsp?data_theme=T_VITAL&data_cube=N_CoD_grouped&u_id=10174727&c_id=10001043&add=Y

NB this system is very much influenced by the DDI Aggregate Data 
Extension, but DDI notions of studies and collections are NOT 
implemented:  this is certainly about a single collection, and we are 
concerned with census and vital registration reports, not with 
"studies".  The system also contains very detailed documentation 
about British census reports, and the tables they have 
contained.  This allows us to reconstruct the original census tables, 
like this:

http://www.visionofbritain.org.uk/census/table_page.jsp?tab_id=EW1951COU_M3&show=DB

However, a major goal of the system is to draw on whole sequences of 
census reports to construct local time series and our DDI 
implementation creates a second alternative context for each data 
value, independent of its place within the original reports, 
establishing reporting continuities over time.  Here is an nCube 
listing covering population totals from 1801 to 2001 for a parish, 
i.e. a single village;  the "Source Info" view is maybe more 
interesting than this graph:

http://www.visionofbritain.org.uk/data_cube_chart_page.jsp?data_theme=T_POP&data_cube=N_TPop&u_id=10078271&c_id=10001043&add=N

Incidentally, all the statistical data are held in just one column of 
a single very large table, currently with 11m+ rows, which is drawn 
on for both the census table reconstructions and the DDI-based time series.

Best wishes,

Humphrey Southall

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    ====================================
Humphrey Southall
Reader in Geography/Director,
Great Britain Historical GIS Project
Department of Geography, University of Portsmouth
Buckingham Building, Lion Terrace, Portsmouth PO1 3HE

GIS Project Office: (023) 9284 2500
Home office:  (020) 8853 0396
Mobile: 0796 808 5454

About Britain:	http://www.VisionOfBritain.org.uk
About us:	http://www.gbhgis.org