Identification info

Metadata Language

English (en)

Dataset Reference Date ()

2016-05

Identifier

http://data.bgs.ac.uk/id/dataHolding/13606926

Maintenance and update frequency

notEntered

GEMET - INSPIRE themes

• Geology

BGS Thesaurus of Geosciences

• Risk management

• Geohazards

• Risk analysis

• Insurance

Keywords

• NERC_DDC

Limitations on Public Access

otherRestrictions

Other constraints

restricted

Other constraints

The dataset has been formally approved by BGS for access by external clients under a BGS Digital Data Licence, issued via BGS's IPR Section. The dataset must not be provided to, or be accessible by, an external client until the IPR Section confirms that signed licence documentation is in place. Refer to the IPR Section (DigitalLE@bgs.ac.) if further advice is required.

Use constraints

otherRestrictions

Other constraints

The copyright of materials derived from the British Geological Survey's work is vested in the Natural Environment Research Council [NERC]. No part of this work may be reproduced or transmitted in any form or by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright holder, via the BGS Intellectual Property Rights Manager. Use by customers of information provided by the BGS, is at the customer's own risk. In view of the disparate sources of information at BGS's disposal, including such material donated to BGS, that BGS accepts in good faith as being accurate, the Natural Environment Research Council (NERC) gives no warranty, expressed or implied, as to the quality or accuracy of the information supplied, or to the information's suitability for any use. NERC/BGS accepts no liability whatever in respect of loss, damage, injury or other occurence however caused.

Other constraints

The dataset is made available to external clients under BGS Digital Data Licence terms and conditions. Revert to the IPR Section (iprdigital@bgs.ac.uk) if further advice is required with regard to permitted usage. iprdigital@bgs.ac The dataset is made available to external clients under BGS Digital Data Licence terms and conditions. Revert to the IPR Section (iprdigital@bgs.ac.uk) if further advice is required with regard to permitted usage.

Spatial representation type

vector

Denominator

50000

Topic category

• Geoscientific information

Extent

GBN

Dataset Reference Date ()

2009

Extent

GREAT BRITAIN [id=139600]

Dataset Reference Date ()

1979

Begin date

1835

End date

2016-05-17

Additional information

The methodology behind the DPD involves balancing the 6 GeoSure natural ground stability hazards against each other. The GeoSure maps themselves have a fivefold coding (A to E), and the balancing exercise involves comparing each level across the six hazards e.g. comparing a level C shrink-swell clay area with a level C running sand area. The comparison is done by estimating how frequently a ground movement event may occur that could have the potential to damage a property (in particular, low-rise buildings). Each level of each of the hazards is given an 'occurrence factor' (as shown in Table 1 of the user guide), which can then be added together to derive a Total Occurrence Factor at a particular location (e.g. within a given postcode). In 2003, the BGS also published a series of GIS digital maps identifying areas of potential natural ground movement hazard in the UK, called GeoSure. There are six separate hazards considered - shrink-swell clays, slope instability, dissolution of soluble ground, running sand, compressible ground and collapsible ground. These maps were derived by combining the rock classification scheme (RCS) information from DiGMapGB-50 with a series of other factors which may cause the geological hazards (e.g. steep slopes, groundwater). In 2007, the BGS used the GeoSure maps to make an interpretation of subsidence insurance risk for the UK property insurance industry, released as the new GeoSure Insurance Product. This represents the combined effects of the 6 GeoSure hazards on (low-rise) buildings in a postcode database - the Derived Postcode Database, which can be accompanied by GIS maps showing the most significant hazard areas. The combined hazard is represented numerically in the Derived Postcode Database as the Total Occurrence Factor, with a breakdown into the component hazards, as described in more detail below. GeoSure Derived Postcode Database (DPD) The DPD is a stand-alone database, which can be provided separately to the visualisation layers in the Full GeoSure Insurance Product.

 

Distribution Information

Data format

• MapInfoFiles

  ()

• ESRI Files

  ()

 

Quality Scope

dataset

Other

dataset

Statement

The sources of the newGIP dataset are the GeoSure v7 product and Ordnance Survey Code-Point® data v2016.1. The postcode centroids layer (OS CodePoint OpenData), as supplied by Ordnance Survey, is buffered using a value of 355 metres for urban postcodes and 405 meters for rural postcodes. These values take into account the 50 metres cartographic precision of the Digital Geological Map of Great Britain at the 1:50,000 scale (DiGMapGB-50) data that is used as the geological basis for the GeoSure hazard layers. The cut-off point between the urban and rural polygons (OS CodePoint with polygons dataset) was determined from the distribution of the area of postcodes and resulted in a figure of 74668.84 m2. The DPD scores are calculated by intersecting each postcode polygon with the Unified Hazards Vector Dataset and calculating the area weighted average of the individual hazard scores within each buffered postcode polygon. Each individual hazard score is then summed to give a total score. The total score is classed into 5 equal classes to produce a Class field. The classes used are Low, Low-Medium, Medium, Medium-High, High.

Metadata

File identifier

34c17086-35f2-33da-e054-002128a47908 XML

Metadata Language

English (en)

Resource type

dataset

Metadata Date

2023-03-31

Metadata standard name

UK GEMINI

Metadata standard version

2.3