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Scottish Executive Urban Rural Classification 2003-2004

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SCOTTISH EXECUTIVE URBAN RURAL CLASSIFICATION 2003-2004

Annex A: Scottish Executive Urban Rural Classification Methodology

Scottish Executive Urban Rural Classification 2003/2004

1. Description

The Scottish Executive (SE) 6-fold and 8-fold urban rural classifications are intended to provide a consistent way of defining urban and rural areas across Scotland. Two main criteria have been used to develop the SE 6-fold and 8-fold urban rural classifications: population as defined by the General Registers Office for Scotland (GROS) and accessibility based on drive time analysis to differentiate between accessible and remote areas in Scotland.

2. Datasets Used

  • Settlements 2001 (based on Census 2001 Output Areas)

The General Registers Office for Scotland (GROS) are responsible for the definition of settlements, a simplified methodology is as follows: A postcode is classed as urban if it has more than 2.1 residential addresses per hectare or it has more than 0.1 non-residential addresses per hectare. Once all the urban postcodes have been identified GROS join neighbouring urban postcodes that together contain more than 210 residential addresses (broadly equivalent to a population of 500) to create a settlement.

The following link describes how GROS define settlements in more detail: http://www.gro-scotland.gov.uk/grosweb/grosweb.nsf/pages/scosett

As part of the 2001 Census GROS published Settlement 2001 population estimates based on aggregations of Census 2001 Output Areas. GROS also released the Output Area index that showed the geographic relationship between Output Areas and the Settlements 2001 dataset.

The settlement population estimates based on Output Areas are the most accurate available and these along with settlement boundaries also built up from Output Areas were used in this project in preference to the postcode derived Settlements 2001 dataset 1. The settlement population estimates and Output Area index can be found on SCROL ( http://www.scrol.gov.uk).

1. The following processes re-created the Settlements 2001 dataset using Census 2001 Output Areas (OA). OA boundaries were joined to the OA index via OA code then those that fell in a Settlement were selected The selected OA were dissolve based on their Settlement code and finally the dissolved dataset was joined to the settlement population estimates based on aggregations of Output Areas.

  • Road network

Derived from Ordnance Survey's OSCAR Route Manager dataset to provide street level mapping and generalised to a scale of 1:50,000, it comes complete with network files to enable the creation of travel times and drive times. It includes motorways, trunk roads, A roads, B roads and the majority of minor and unclassified roads, the exceptions are cul-de-sacs less than 200 metres in length, pedestrianised streets, private roads and ferry routes.

3. Methodology

The first stage in creating the SE classifications was to look at settlement populations. Settlements were categorized into the following 4 groups:

  • Large urban areas: Settlements of 125,000 or more, which have a wide range of services.
  • Other urban areas: Settlements of 10,000 or over and below 125,000, which have a good range of services.
  • Small towns: Settlements of 3,000 or over and below 10,000. These are likely to be smaller towns which are unlikely to contain a full range of services.
  • Rural: Settlements below 3,000 and those not living in settlements. These are unlikely to contain many services.

The next stage was to distinguish between accessible and remote areas. This was done by creating a 30 minute drive time for the 6-fold classification and a 30 and additional 60 minute drive time for the 8-fold classification from settlements of size 10,000 or more. Thus creating the following definitions of remoteness:

  • Accessible: 30 minutes or less drive time from a settlement of 10,000 or over
  • Remote: more than a 30-minute drive time from a settlement of 10,000 or over (or between a 30 and 60 minute drive time for the 8-fold classification)
  • Very Remote: more than a 60 minute drive time from a settlement of 10,00 or over (8-fold classification only)

The 30 and 60 minute drive time boundaries were created using drive time software from the population weighted centroids of all settlements with a population of 10,000 or over; centroid co-ordinates were supplied by GROS. Settlements with a population of 10,000 or more located in England but within a 30 minute drive time of Scotland were also included in the in the analysis (i.e. Berwick-upon-Tweed and Carlisle).

Drive time calculations are based on average travel speeds. Each of the road classes (e.g. A roads or B roads) in the road network have an assigned speed. This speed is the average for that class (figures come from DETR) but the process does not take into account peak and non-peak travel times.

Road class, description and average speed used in the analysis.

Road Class

Description

Speed (kmph)

A Road

Rural

65

A Road

Small Urban

40

A Road

Large Urban

35

A Road

Inner Urban

25

A Road

Conurbation Central Core

20

A Road

Central London

10

B Road

Rural

55

B Road

Small Urban

35

B Road

Large Urban

30

B Road

Inner Urban

25

B Road

Conurbation Central Core

15

B Road

Central London

10

Motorway

Rural

105

Motorway

Small Urban

85

Motorway

Large Urban

80

Motorway

Inner Urban

62

Motorway

Conurbation Central Core

55

Motorway

Central London

55

Trunk Road

Rural

70

Trunk Road

Small Urban

40

Trunk Road

Large Urban

35

Trunk Road

Inner Urban

25

Trunk Road

Conurbation Central Core

20

Trunk Road

Central London

10

Unclass Road

Rural

40

Unclass Road

Small Urban

30

Unclass Road

Large Urban

25

Unclass Road

Inner Urban

20

Unclass Road

Conurbation Central Core

15

Unclass Road

Central London

10

The 30 and 60 minute drive time boundaries were combined to form a single dataset.

Each settlement was initially classed depending on its estimated population. With the creation of a drive time dataset each settlement was also classed depending on its distance from a settlement with a population of 10,000 or more. In some cases drive time boundaries split a settlement. The method used here treats settlements as whole entities and classify them based on the drive time their centroid fell in.

Finally, settlements and drive time datasets were combined to form one national dataset containing both the 6 and 8-fold definitions.