The map shows the building bricks of output geography.

The basic unit is a co-ordinate reference for each address, taken mainly from the Ordnance Survey Address Point ™ product, but augmented from information returned in the Census. No information whatsoever is released on or about individual addresses.

A bounded zone is created automatically around the addresses in each unit postcode. Some postcodes cross boundaries of areas for which Census statistics are presented, and information on the split is held in the system. Unit postcode boundaries are not released, but headcounts of males, females and households are available for each unit postcode.

Postcodes are grouped into Output Areas which meet mandatory criteria of population size and contiguity and which optimise criteria of shape and homogeneity. Output Areas nest within one set of ward boundaries - these legally in force on 31 December 2002.

Click HERE to access the Website prepared by Professor David Martin of the University of Southampton, this provides a detailed account of the methods used in the Output Area system.

This map is reproduced from Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings (ONS.GD272183.2001).

Key:
	address point, used to build postcode zones
	postcode boundary
	OA boundary (which overlies the red postcode boundaries in places, since postcodes nest within OAs)
	ward boundary (which overlies the black boundaries in places, since OAs nest within wards)
	represents a postcode split between two wards. The diagram shows this as allocated to two OAs, one on either side of the ward boundary.

This page last revised: 01 November 2005