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Geography hierarchy

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The MAST Geography hierarchy is used to identify geographical locations in a consistent way. It is based on the local authority geography of Britain. The smallest geographical unit represented in this hierarchy are local authority districts (in two tier counties), or unitary authorities elsewhere.

Each location represented in this hierarchy has a single letter prefix which indicates its type and level, explained in greater detail below. It is further identified by an eight letter abbreviation of the location name, separated from the prefix by an underscore. For example R_EastMids is the East Midlands of England; G_WalGwynd is the geographical county of Gwynedd (consisting of the unitary authority areas of Gwynedd and Anglesey); and C_Somerset includes all districts within Somerset county council (but excludes other unitary authority areas in the geographical county of Somerset).

This hierarchy is used to identify locations for where crashes took place (called Crash Location), where drivers reside (called Driver Home) and also where casualties reside (called Casualty Home).

Using the Geography hierarchy as a report filter can activate the Show Similar Authorities feature.

A general introduction to the geography of the UK can be found on the National Statistics website.

The Geography hierarchy is organised into multiple levels. each level is explained in more detail in the sections below.



The top level of the hierarchy is a single area which represents the whole of the UK, including Northern Ireland but excluding the Channel Islands and the Isle of Man.


This level contains the countries of the UK, Including Northern Ireland. Because MAST does not contain STATS19 data for Northern Ireland, there are no crashes located there.


This level refers to the areas formerly covered by the Government Office regions of England. MAST will continue to use these areas because they are convenient way to categorise parts of England on a regional basis, even though regional government offices as such no longer exist. The other countries of the UK are shown as a single region at this level.

All short region names are prefixed with R_.

Police Force Area

This level contains the Police Forces within each region.

The City of London Police are not shown separately at this level, because they do not produce separate STATS19 returns. However, the force area can be taken as congruent with that of the City of London Corporation, which is represented alongside the London Boroughs at Highways authority level.

All short police force names are prefixed with P_.

Geographical County

This level contains useful geographical subdivisions within police forces. All short names of these areas are prefixed with G_. Different considerations apply to each country of the UK for setting the areas appropriate for this level. These are discusssed in detail below.


The areas used are based on the ceremonial counties as defined by Parliament, which are virtually congruent with local authority boundaries. However, because ceremonial county boundaries are not always congruent with those of police force areas, some counties cannot be shown as a single area.

For example, because police and regional boundaries were established at a time when the former county of Humberside existed, the ceremonial county of Lincolnshire is divided into two areas:

  • G_LincCS&W, corresponding to Lincolnshire County Council, which comes under Lincolnshire Police in the East Midlands region
  • G_LincN&E, corresponding to the unitary authorities of North Lincs and NE Lincs, which come under Humberside Police in the Yorkshire and Humberside region

Similar considerations apply to areas once covered by the former counties of Avon and Cleveland.


No single uniform list of geographical areas congruent with current local government boundaries exists for Scotland. Instead, the following principles have been applied:

  • The four largest cities in Scotland are shown separately from the remainder of the police force areas in which they lie
  • Locales in each police force which lie outside the four big cities have generally been shown as a single area at this level
  • In three cases, it has been considered helpful to split such areas further:
    • The unitaries corresponding to the historic counties of Strathclyde have been shown as distinct areas within Strathclyde Police
    • The Island unitaries are grouped together, separate from the mainland area covered by Northern Police
    • The Borders unitary authority (which was formerly the Borders Region) has been shown separately from the Lothian unitaries covered by Lothian and Borders Police


The eight preserved county areas as defined by the Welsh Assembly have been used. These areas are ideal for use as an intermediate level between police force and unitary authority level, because they have been intentionally designed to be congruent with existing police and local authority boundaries.

Highway authority

This level contains local authorities which act as highway authorities. This includes both county councils and unitary authorities of all kinds, such as London Boroughs, Metropolitan districts and Scottish and Welsh councils.

Short highways authority names are prefixed with C_ for county councils, or U_ for unitary authorities.

Any report filtered by a single authority at this level is suitable for use with the Similar authorities feature.


This level contains district authorities within two tier counties. Unitary authorities do not contain any subdivision at this level.

Short local authority district names are prefixed with L_.

Any report filtered by a single authority at this level is suitable for use with the Similar authorities feature.

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