This technical specification provides detailed technical information about Code-Point. It is targeted at technical users and software developers.
Code-Point is a dataset that contains postcode units for Great Britain and Northern Ireland, each having a notional geographical location. Postcodes are an alphanumeric abbreviated form of an address. Postcode units are unique references and identify an average of 15 addresses. In some cases, where an address receives a substantial amount of mail, a postcode will apply to only one address and is defined as a large-user postcode. The maximum number of addresses in a postcode is 100.
| Attribute | Description |
|---|---|
Each postcode unit location – also known as CPLC (Code-Point Location Co-ordinate) – is coordinated on the respective National Grid, with eastings and northings quoted to a resolution of 1m. The accuracy of each postcode unit coordinate pair is defined by the positional quality indicator (PQI), which provides a quality statement of that Code-Point record. There are seven PQI values for the positional quality:
| PQI | Description |
|---|---|
Postcode
Contains elements for postal area, district, sector, and unit.
Positional quality indicator (PQI)
A flag used to indicate the positional accuracy of the coordinates allocated to each postcode record.
PO Box indicator
Denotes if the postcode is a PO Box.
Total delivery points
The total number of both matched and unmatched delivery points in the postcode. Not in BT data for Northern Ireland.
Delivery points
Number of matched addresses in the postcode unit that have a PQI of 10 or 20. Not in BT data for Northern Ireland.
Domestic delivery points
Number of non PO box delivery points that have no PAF organisation name. Not in BT data for Northern Ireland.
Non domestic delivery
Number of non PO box delivery points that have a PAF organisation name. Not in BT data for Northern Ireland.
PO Box domestic delivery points
Number of PO Box delivery points. Not in BT data for Northern Ireland or where PQI is 20 in Scotland.
Matched addressed premises
Number of delivery points in buildings or building subdivisions, after exclusion of duplicated coordinate pairs. Not in BT data for Northern Ireland or where PQI is 20 in Scotland.
Unmatched delivery points
Number of delivery points awaiting improvement on location. Not in BT data for Northern Ireland or where PQI is 20 in Scotland.
Easting
Distance in metres east of National Grid origin.
Northing
Distance in metres north of National Grid origin.
Country code
Code used by ONS to identify the country in which the Code Point georeferenced coordinates lies.
NHS regional health authority code
English Pan Strategic Health Authority in which CPLC falls.
NHS health authority code
English Strategic Health Authority or Scottish Health Board in which CPLC falls.
Administrative county code
County in which CPLC falls.
Administrative district code
Unitary Authority, Metropolitan and Non- Metropolitan District, London Borough or Scottish Council Area in which CPLC falls.
Administrative ward code
Electoral Ward or Division in which CPLC falls.
Postcode type
Indicates whether the user is large, L, or small, S. Large postcode type users receive more than 500 pieces of mail. Small users receive 70 pieces per day.
10
Within the building of the matched address closest to the postcode mean determined automatically by Ordnance Survey (or Land & Property Services for the BT postcode area only).
20
As above but determined by visual inspection by National Records of Scotland (NRS).
30
Approximate to within 50m of the true position (postcodes relating to developing sites may be within 100m of true position).
40
The mean of the positions of addresses previously matched in PALF but which have subsequently been deleted or recoded (very rarely used).
50
Estimated position based on surrounding postcode coordinates, usually to 100m resolution, but 10m in Scotland.
60
Postcode sector mean.
90
No coordinates available.
GeoPackage is an open, standard, platform-independent, portable, self-describing, compact format for transferring geospatial information. For more information on this format, please see the Getting started with GeoPackage guide, available here.
The following tables give a comparison between the CSV attributes and the GeoPackage attribution.
| Mnemonic | Description | Data type | Size |
|---|---|---|---|
Those fields containing text (A) will be enclosed by double quotes which have not been included in the sizes listed in the table above. An asterisk (*) denotes variable length.
Fields with null data will appear as "" for text and 0 for numeric.
Each record will be terminated with a carriage return character (ASCII 13) and a line feed character (ASCII 10).
Example of a Code-Point CSV record: "SO160AS",10,"N",1,1,0,1,0,1,0,437292,115542,"E92000001","E19000002","E18000009","E10000014","E07000093","E05012936","L"
Note that there are no eastings or northings in GeoPackage; the geometry is already created in the GeoPackage container and is not listed as data but will be seen as a column in a database (PostGIS) called geom with a coordinate reference system of British National Grid EPSG: 27700 for GB postcodes.
Also supplied with the GeoPackage is the Code-Point data for Northern Ireland. This is already projected in Irish Grid EPSG: 29902 so will display in the correct position for this region.
Fields with a null value will appear as [Null] for text (PostGIS) or as an empty field in a GIS. A null numeric value will appear as 0 in both a database and an attribute table in a GIS. Example of a GeoPackage record taken from the Information tool in QGIS:
The FeatureID (FID) is autogenerated by a GIS when the GeoPackage is loaded into it; it is not present in the GeoPackage.
| Description | Data type | Size |
|---|---|---|
PC
Postcode
A8
8
PQ
Postitional_quality_indicator
I2
1
PR
PO_Box_indicator
A1
1
TP
Total_number_of_delivery_points
I3
*
DQ
Delivery_points_used_to_create_the_CPLC
I3
*
RP
Domestic_delivery_points
I3
*
BP
Non_domestic_delivery_points
I3
*
PD
PO_Box_delivery_points
I3
*
MP
Matched_address_premises
I3
*
UM
Unmatched_delivery_points
I3
*
EA
Eastings
I6
*
NO
Northings
I7
*
CY
Country_code
A9
9
RH
NHS_regional_HA_code
A9
9
LH
NHS_HA_code
A9
9
CC
Admin_county_code
A9
9
DC
Admin_district_code
A9
9
WC
Admin_ward_code
A9
9
LS
Postcode_type
A1
1
postcode
TEXT
8
positional_quality_indicator
TINYINT
1
po_box_indicator
TEXT
1
total_number_of_delivery_points
TINYINT
*
delivery_points_used_to_create_the_cplc
TINYINT
*
domestic_delivery_points
TINYINT
*
non_domestic_delivery_points
TINYINT
*
po_box_delivery_points
TINYINT
*
matched_address_premises
TINYINT
*
unmatched_delivery_points
TINYINT
*
N/A
N/A
N/A
N/A
N/A
N/A
country_code
TEXT
9
nhs_regional_ha_code
TEXT
9
nhs_ha_code
TEXT
9
admin_county_code
TEXT
9
admin_district_code
TEXT
9
admin_ward_code
TEXT
9
postcode_type
TEXT
1