THE WEB-BASED INTERFACE TO THE WEB-BASED INTERFACE TO CENSUS INTERACTION DATA - CENSUS INTERACTION DATA -

WICIDWICIDPresentation to the ESRC Research Methods Festival Presentation to the ESRC Research Methods Festival

Adam DennettAdam DennettCentre for Interaction Data Estimation and ResearchCentre for Interaction Data Estimation and Research

School of GeographySchool of GeographyUniversity of LeedsUniversity of Leeds

PRESENTATION OUTLINEPRESENTATION OUTLINE

• Brief background to interaction data access• The requirements and design of the WICID

interface• System architecture and metadata• Accessing WICID and basic interface functions• Advanced interface functions• Future developments

THE ACCESS PROBLEMTHE ACCESS PROBLEM

• For many years access to interaction data was not straightforward. The evolution of computer technology made access easier, but not easy.

• Programmes such as MATPAC, SMSTAB, SWSTAB and QUANVERT; powerful tools but not user friendly – command-line driven.

• In order to encourage wider usage through facilitating easy access to the data, the Web-based Interface to Census Interaction Data (WICID) was constructed.

Background to interaction data accessBackground to interaction data access

WICIDWICID

• WICID was designed with a number of specific requirements in mind:

1. The interface must be user friendly. It must facilitate query building, quick data extraction and simple downloading of files by non-expert users.

2. The interface should provide access to library of popular data sub-sets and their associated pre-defined queries.

3. The interface must be flexible to allow for the addition of new datasets

Interface design and requirementsInterface design and requirements

WICIDWICID

4. Where flows can be measured between multiple origins and destinations of differing sizes, the selection of geographies should be made as simple as possible

5. Users should be assisted in building queries through the provision of alternative variable selection methods

6. The system (if not the data contained) should be made available to other parties, thus should be constructed though free/open source components

Interface design and requirementsInterface design and requirements

WICIDWICIDSystem architecture and metadataSystem architecture and metadata

Web browser client:IE, Firefox, Opera, etc…

Web server:Apache 2.0.59,

supporting php 5

Database Server:PostgreSQL 8.2.4

Session Data

Interaction Data

Meta Data

User View

Web server

DBMS

WICIDWICID

• Underpinning the whole system are the three datasets held within the DBMS:

• Interaction datasets and their associated geographies are clearly fundamental. WICID stores various tables from:– Special Migration Statistics (SMS) Special Workplace Statistics

(SWS) and Special Travel Statistics (STS) at a variety of geographical scales from 1981, 1991 and 2001 Censuses.

– Geographical data and look-up tables also stored• Metadata are equally fundamental as the system has no

‘hard-coded’ data; without these data in place to describe the interaction data to the system, WICID would not be able to function

• Session data are used by the system to remember which options have been selected by users during the query process – key in a system with multiple pages and options

System architecture and metadataSystem architecture and metadata

WICIDWICID

http://www.cider.census.ac.uk

Accessing WICIDAccessing WICID

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICIDBasic Interface FunctionsBasic Interface Functions

WICIDWICID

• As well as the standard query building interface functions, WICID offers a selection of additional features:– Downloading of population data with flow data– Facility to derive new variables from existing

variables– Analysis functions – Customised help system

Additional Interface FunctionsAdditional Interface Functions

WICIDWICID

• PAR data are required for rate calculations. Where comparable PAR are available for flow data, WICID will find and add these data to the selection for download

• WICID will aggregate PAR data to exactly the same level as the selected origins or destinations, thus allowing for simple post-extraction calculations to be made

Populations at RiskPopulations at Risk

WICIDWICIDPopulations at RiskPopulations at Risk

WICIDWICID

• The derive option allows users to create new aggregate variables from those already in existence in the SMS and SWS tables.

• The derive function is particularly useful where there may be too much disaggregation in the original data e.g. all 7 ethnic groups could be re-aggregated into just ‘white’ and ‘other ethnic groups’ categories before download

Deriving new variablesDeriving new variables

• After selecting variables, clicking the ‘derive’ link underneath the table allows any of the chosen variables to be combined into a new variable e.g. 0-15 or 16-29 etc.

WICIDWICID

• WICID has a suite of analysis functions which can be used to interrogate extracted data (either for the entire matrix, in-flows or out-flows), these include:

• Basic statistics – Min, Max, Mean, Median, Sample standard deviation, Coefficient of variance.

• Correlation statistics• Distance travelled (mean or median for each variable)• Indices of connectivity and inequality • Index of migration effectiveness• Crude intensities (in/out migration rates and matrix

rate)

Analysis functionsAnalysis functions

WICIDWICIDAnalysis functionsAnalysis functions

WICIDWICIDHelp systemHelp system

WICIDWICID

• WICID’s inbuilt flexibility means that it will easily be able to incorporate additional (Census and non-Census) datasets as and when they become available.

• The only requirement is that future data follow the origin/destination/variable format. Current data have arrived for discrete time periods, in future there is no reason why more continuous interaction data could not be added in an origin/destination/variable/time reference format.

• Prior to the release of 2011 Census data, WICID will be providing access to annual patient registration/NHSCR data from 2001 at Health Authority level.

• An on-going programme of minor interface updates and improvements

Future developmentsFuture developments