The MAST Geography dimension is used to identify geographical locations in a consistent way. It is based on the local authority geography of Britain, and the lowest level currentyl represented are local authority districts in two tier counties, or unitary authorities elsewhere.
The Geography dimension is organised into multiple hierarchical levels, as follows:
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 locationed there. However, any drivers or casualties who are resident in Northern Ireland will be shown.
This level contains the Government Office regions of England. 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.
All short police force names are prefixed with P_.
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, 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
- 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 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.
This level contains local authorities which act as highway authorities. This includes both county councils and unitary authorities.
Short highways authority names are prefixed with C_ for county councils, or U_ for unitary authorities.
This level contains district authorities within two tier counties. Unitary authorities do not contain any subdivision at this level.
Short district names are prefixed with D_.