Why Area_Ids arent published in the UK for polygons

Why Area_Ids are not published in the UK for polygons?

Many customers will ask why they can't find area_ids for the BUA and City Polygons in the UK; as they can find in other countries. The reason they want to do this normally, is so that they can associate a given polygon to a specific admin hierarchy.

However, there isn’t really a correlation between the cartos and the admins in the UK – they represent two different things. Many will match on name, others wont.

Cartos = government areas (or at the lowest level just our BUA polygons)

Admin = The Royal Mail postal structure which is what is used for destination selection, geocoding, etc,

Here is something that explains the situation:

There is no relationship between the administrative information applied to the links for destination selection (i.e. RDF_ADMIN_PLACE etc) and the admin area boundaries (RDF_CARTO).

This reflects reality. The postal service in the UK (Royal Mail) is the source for the admin info applied to the links – this is the system people use to refer to addresses e.g. when sending mail, selecting a destination.

The administrative boundaries (900101 and 900170) represent local government areas – these are the areas which determine where local taxes are paid etc. These area names are not used for addressing.

This mismatch between the admin polygons and the postal system applied to the links is demonstrated in the enclosed image, the highlighted yellow area represents the admin polygon for Manchester (admin level 4 / order 8) and the links in red are the links which have the Royal Mail post town of Manchester applied to them. Note how the two areas simply don’t match up.



So if you only used the Carto to define ‘Manchester’, you would miss a huge amount of data that is assigned to Manchester by the Royal Mail. It really depends on the use case. If you need to define those streets which are within the City of Manchester for say defining service provision, then the Cartos should be used to define a spatial query.

Therefore, we couldn't risk associating the polygons to the admin hierarchy incase customers misuse it and get very bad results. Keeping them separate was the safest option.