> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/areas-and-zones-portfolio/boundary-line/boundary-line-technical-specification/shapefile-tab-and-gkpg/features-shapefile-tab-and-gpkg/area-gb.md).
# Area - GB
Area features are polygons with attributes added.
{% hint style="info" %}
The following schema applies to all area features in the `GB` folder of the shapefile, MapInfo TAB and GeoPackage data supply, and for all area features in the `Supplementary_Country` folder of the shapefile, MapInfo TAB and GeoPackage data supply.
{% endhint %}
## Feature type attributes
The following sub-sections provide details about the attributes included with this feature type, their data types in the different output formats, and other important metadata about them.
### fid
Feature identifier added by the software.
* **Attribute Name**: fid (GPKG), Not provided (TAB), Not provided (Shapefile)
* **Multiplicity**: \[1]
### Shape
Feature geometry.
* **Attribute Name**: Not provided (GPKG), Not provided (TAB), SHAPE (Shapefile)
* **Data Type**: Polygon
* **Multiplicity**: \[1]
### Name
Name of the administrative area.
* **Attribute Name**: Name (GPKG), Name (TAB), NAME (Shapefile)
* **Data Type**: char
* **Size**: 100
* **Multiplicity**: \[0..1]
### Area code
A code describing the level.
* **Attribute Name**: Area\_Code (GPKG), Area\_Code (TAB), AREA\_CODE (Shapefile)
* **Code List Name**: [AreaCode](/os-downloads/products/areas-and-zones-portfolio/boundary-line/boundary-line-technical-specification/shapefile-tab-and-gkpg/code-lists-shapefile-tab-and-gkpg/areacode.md)
* **Size**: 3
* **Multiplicity**: \[1]
### Area description
Full name of the Area\_Code.
* **Attribute Name**: Area\_Description (GPKG), Area\_Description (TAB), DESCRIPTIO (Shapefile)
* **Data Type**: char
* **Size**: 50
* **Multiplicity**: \[1]
### File name
Name of the Principal Area which the boundary sits within.
{% hint style="info" %}
This may be the same boundary level as the boundary itself, for example, a Greater London Authority boundary will have ‘Greater London Authority’ present in this field. But for more granular boundaries, this field will show the principal boundary which is at the principal level.
{% endhint %}
* **Attribute Name**: File\_Name (GPKG), File\_Name (TAB), FILE\_NAME (Shapefile)
* **Data Type**: char
* **Size**: 100
* **Multiplicity**: \[1]
### Feature serial number
Serial Number applied to the Boundary Feature during the production of the product.
{% hint style="info" %}
This is not the unique key for this product and is not maintained.
{% endhint %}
* **Attribute Name**: Feature\_Serial\_Number (GPKG), Feature\_Serial\_Number (TAB), NUMBER (Shapefile)
* **Data Type**: Integer (TAB), Double (Shapefile)
* **Size**: 11 (TAB), n/a (Shapefile)
* **Multiplicity**: \[1]
### Collection serial number
Collection Serial Number applied to the Boundary Feature during the production of the product.
{% hint style="info" %}
This is not the unique key for this product and is not maintained.
{% endhint %}
* **Attribute Name**: Collection\_Serial\_Number (GPKG), Collection\_Serial\_Number (TAB), NUMBER0 (Shapefile)
* **Data Type**: Integer (TAB), Double (Shapefile)
* **Size**: 11 (TAB), n/a (Shapefile)
* **Multiplicity**: \[1]
### Global polygon ID
A globally unique sequential integer-maintained identifier.
* **Attribute Name**: Global\_Polygon\_ID (GPKG), Global\_Polygon\_ID (TAB), POLYGON\_ID (Shapefile)
* **Data Type**: Integer (TAB), Double (Shapefile)
* **Size**: 11 (TAB), n/a (Shapefile)
* **Multiplicity**: \[1]
### Admin unit ID
A globally unique sequential integer-maintained feature identifier. There are two cases where multiple records have the same UNIT\_ID:
1. When portions of local government or parliamentary constituency areas are separated from the main area, being completely surrounded by other local government or parliamentary constituency areas and not connected by direct access on the ground. Not applied to islands or parts of islands in the sea. Detached parts have the same attributes as the main area, except the POLYGON\_ID and the Name which has a ‘(DET)’ suffix. In all the existing examples, there is exactly one detached part.
2. In Scotland, two examples where the boundary has thousands of parts, so the multi-polygon is broken into simple polygons to make it easier to handle. The examples are the supplementary country\_region layer where NAME=‘SCOTLAND\_COUNTRY’ and scotland\_and\_wales\_region where NAME='Highlands and Islands PER'.
* **Attribute Name**: Admin\_Unit\_ID (GPKG), Admin\_Unit\_ID (TAB), UNIT\_ID (Shapefile)
* **Data Type**: Integer (TAB), Double (Shapefile)
* **Size**: 11 (TAB), n/a (Shapefile)
* **Multiplicity**: \[1]
### Census code
Set to the Census / GSS Code for the boundary, for example, E10000014.
* **Attribute Name**: Census\_Code (GPKG), Census\_Code (TAB), CODE (Shapefile)
* **Data Type**: Char
* **Size**: 9
* **Multiplicity**: \[0..1]
### Hectares
Set to the Census / GSS Code for the boundary, for example, E10000014.
* **Attribute Name**: Hectares (GPKG), Hectares (TAB), HECTARES (Shapefile)
* **Data Type**: Char
* **Size**: 9
* **Multiplicity**: \[1]
### Non-inland area
Amount of area within the boundary which is not considered ‘inland’. Non-inland areas are calculated by comparing the Boundary-Line polygons with the Mean High Water lines. The value is in hectares and represents the area between the Mean High Water line and the seaward limit of the boundary denoting Mean Low Water.
* **Attribute Name**: Non\_Inland\_Area (GPKG), Non\_Inland\_Area (TAB), AREA (Shapefile)
* **Data Type**: Decimal (TAB), Double (Shapefile)
* **Size**: 12 (TAB), n/a (Shapefile)
* **Multiplicity**: \[1]
### Area type code
Code depicting whether the boundary is part of a Civil Administration Area, a Civil Voting Area.
* **Attribute Name**: Area\_Type\_Code (GPKG), Area\_Type\_Code (TAB), TYPE\_CODE (Shapefile)
* **Code List Name**: [TypeCode](/os-downloads/products/areas-and-zones-portfolio/boundary-line/boundary-line-technical-specification/shapefile-tab-and-gkpg/code-lists-shapefile-tab-and-gkpg/typecode.md)
* **Size**: 2
* **Multiplicity**: \[1]
### Area type description
Full description of TYPE\_CODE.
* **Attribute Name**: Area\_Type\_Description (GPKG), Area\_Type\_Description (TAB), DESCRIPT0 (Shapefile)
* **Data Type**: Char
* **Size**: 25
* **Multiplicity**: \[0..1]
### Non-area type code
Shouldn’t be populated.
* **Attribute Name**: Non\_Area\_Type\_Code (GPKG), Non\_Area\_Type\_Code (TAB), TYPE\_COD0 (Shapefile)
* **Data Type**: Char
* **Size**: 3
* **Multiplicity**: \[0..1]
### Non-area type description
Shouldn’t be populated.
* **Attribute Name**: Non\_Area\_Type\_Description (GPKG), Non\_Area\_Type\_Description (TAB), DESCRIPT1 (Shapefile)
* **Data Type**: Char
* **Size**: 36
* **Multiplicity**: \[0..1]
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