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National Statistics Postcode Directory |
What is the NSPD?
The National Statistics Postcode Directory (NSPD) is a list of all the current and terminated postcodes
that have ever existed in the UK, together with geographical links or matches for each postcode to a variety
of different administrative, health, electoral and other geographies that are, or have been, used within the UK.
The NSPD also contains a range of useful information about the postcodes themselves such as grid references,
address counts, area classifications, urban/rural classifications, etc.
Updated versions of the NSPD are produced every three months by the Office for National Statistics (ONS), with
input from the General Register Office for Scotland (GROS), the Northern Ireland Statistics and Research Agency
(NISRA), Royal Mail and Ordnance Survey. The NSPD dataset has a simple flat file structure, but is very large.
The most recent version at the time of writing has approximately 2.4 million rows (one for each postcode),
each with 52 columns of information about the postcodes, and has a size of around 1.5 gigabytes when uncompressed.
It is likely that future versions of the NSPD will grow in size if the trend for the number of postcodes used in
the UK to increase, and for additional columns of information to be added to the NSPD, continues.
What can the NSPD tell us?
The NSPD explicitly provides information about postcodes, their locations and their relationships to other
geographies, but it can also be used to derive information about relationships between all of the other
geographies included in the NSPD through analysis of shared postcodes.
How can the NSPD be used?
The information contained within the NSPD has a wide range of potential uses across a broad range of disciplines
wherever postcode data is used, or where information on the relationships between different geographies, or changes
in a single geography over time is required. Some of the ways in which the information contained in the NSPD is
used include:
- location of postcoded data by obtaining grid references from the NSPD for point mapping and spatial analysis
- matching of postcodes to primary care trusts to enable combination of postcoded data with health data for choropleth mapping
- matching of postcodes to lower layer super output areas for which Indices of Deprivation 2004 scores are available for the profiling of student intakes as part of widening participation work within academic organisations
- investigation of the relationships between 1991 census wards and 2001 census CAS wards to enable comparison of information from the two censuses
Obtaining the NSPD data
Current and historical versions of the NSPD and its precursors, together with original ONS supporting
documentation can be downloaded from
UKBORDERS.
GeoConvert
GeoConvert
is an online service developed by the Census Dissemination Unit (CDU) that
uses information derived from the NSPD to provide users with functions to perform a range
of the tasks for which the NSPD is commonly used without the need to work with the dataset directly.
Geoconvert's functions allow users to:
- obtain information relating to postcodes (e.g. deprivation scores, grid-reference co-ordinates, urban/rural indicators, area classifications, etc)
- obtain population-based proportional redistributions between the zones of different geographies
- convert population-related data from the zones of one geography to those of another
The main aims of GeoConvert are to simplify and expand the use made of the information contained
in the NSPD within the UK academic community by the provision of functions to meet growing requirements
for handling and combining geographical data. It is hoped that the service will save an enormous amount
of duplicated time and effort by providing functions that are quick and easy to use, and are based upon
robust and consistent methods, details of which will soon be available from the GeoConvert interface.
Mechanisms for the rapid, automated incorporation of information from future releases of the NSPD have been
developed as a major component of the GeoConvert project. This will allow regular updates of the geographies
available within the new service in order to maintain the currency of the system.
These resources are available free of charge, via federated access management (Shibboleth) user authentication,
to members of UK higher and further education institutions.
Registration
via Census.ac.uk and agreement to a Special Condition relating to the use of information contained in the NSPD
are required.
Further information
Further information about the NSPD can be found in the supporting documents produced by ONS
to accompany the dataset. These are available alongside downloads of the NSPD from
UKBORDERS, or
from within
GeoConvert.
Information about the different geographies included within the NSPD is available from the
ONS Beginner’s Guide to UK Geographies.