Calculation used in Code-Point with Polygon (FOI241233)

This Freedom of Information request asks for details of the types of major physical features used in the calculation of postcode polygons

Request for information - Ref no: FOI241233

May 8, 2024

Information request

We received your request on 26 March 2024.

We have handled your request under the Freedom of Information Act (FOIA) 2000.

A copy of your request is set out in the extract below:

“The "Code-Point with Polygons" overview document [1] details how the postcode polygons have been automatically computed using a Thiessen process.

It says that "The boundary encloses every delivery address for which positional data of sufficient quality is available, and which follow major physical features that could reasonably be regarded as part of the postcode boundary".

Could you please enumerate the types of "major physical features" used in this calculation, and if the type has different size classes (such as roads or waterways) which classes are used and ignored.”

Our response

I confirm that Ordnance Survey does hold the information you have requested.

I confirm that the product must, “wherever it is possible without moving the boundary to the wrong side of an address, maintain the alignment of the unit postcode boundaries to motorways, railways, rivers and canals, A roads and B roads and other topological features, in that order of priority”.

Next steps

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Ordnance Survey
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SO16 0AS

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