newGeoSure Insurance Product version 7 2015.1
newGIP v7 2015
The newGeoSure Insurance Product (newGIP) provides the potential insurance risk due to natural ground movement. It incorporates the combined effects of the 6 GeoSure hazards on (low-rise) buildings. This data is available as vector data, 25m gridded data or alternatively linked to a postcode database – the Derived Postcode Database. A series of GIS (Geographical Information System) maps show the most significant hazard areas. The ground movement, or subsidence, hazards included are landslides, shrink-swell clays, soluble rocks, running sands, compressible ground and collapsible deposits. The newGeoSure Insurance Product uses the individual GeoSure data layers and evaluates them using a series of processes including statistical analyses and expert elicitation techniques to create a derived product that can be used for insurance purposes such as identifying and estimating risk and susceptibility. The Derived Postcode Database (DPD) contains generalised information at a postcode level. The DPD is designed to provide a ‘summary’ value representing the combined effects of the GeoSure dataset across a postcode sector area. It is available as a GIS point dataset or a text (.txt) file format. The DPD contains a normalised hazard rating for each of the 6 GeoSure themes hazards (i.e. each GeoSure theme has been balanced against each other) and a combined unified hazard rating for each postcode in Great Britain. The combined hazard rating for each postcode is available as a standalone product. The Derived Postcode Database is available in a point data format or text file format. It is available in a range of GIS formats including ArcGIS (*.shp), ArcInfo Coverages and MapInfo (*.tab). More specialised formats may be available but may incur additional processing costs. The newGeoSure Insurance Product dataset has been created as vector data but is also available as a raster grid. This data is available in a range of GIS formats, including ArcGIS (*.shp), ArcInfo coverage’s and MapInfo (*.tab). More specialised formats may be available but may incur additional processing costs. Data for the newGIP is provided for national coverage across Great Britain. The newGeoSure Insurance Product dataset is produced for use at 1:50 000 scale providing 50 m ground resolution. This dataset has been specifically developed for the insurance of low-rise buildings. The GeoSure datasets have been developed to identify the potential hazard for low-rise buildings and those with shallow foundations of less than 2 m deep. The identification of ground instability and other geological hazards can assist regional planners; rapidly identifying areas with potential problems and aid local government offices in making development plans by helping to define land suited to different uses. Other users of these data may include developers, homeowners, solicitors, loss adjusters, the insurance industry, architects and surveyors. Version 7 released June 2015.
dataset
http://www.bgs.ac.uk/products/geohazards/geosureInsurance.html
function: information
http://data.bgs.ac.uk/id/dataHolding/13606634
eng
OGP
urn:ogc:def:crs:EPSG::27700
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.
geoscientificInformation
publication
2008-06-01
Natural hazards
revision
2011
NERC_DDC
-8.1700
2.6900
60.8100
49.8800
revision
2009
ENG
creation
1979
ENGLAND [id=150000]
creation
1979
SCOTLAND [id=140000]
revision
2009
SCT
creation
1979
WALES [id=170000]
revision
2009
WLS
2015
creation
2015
biannually
In detail, the methodology behind producing the DPD is as follows: 1. The postcode centroids layer, as supplied by Ordnance Survey, is buffered using a value of 300 metres. This value takes into account the variability in size of postcodes (250 metres) and 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. 2. An 'occurrence rating' is then assigned to each of the A-E levels of each master GeoSure hazard layer. These occurrence ratings represent how frequently a ground movement event may occur that could have the potential to damage a property (in particular, low-rise buildings). The occurrence ratings are then multiplied by a nominal score (100) in order to derive a series of 'unified ratings'. Before use in the DPD, these unified rating values in the table are then multiplied by 10 allow the use of integer values. For example a class 'D' shrink-swell pixel will have a value of 10 x 10 = 100. 3. Zonal statistics are then calculated using the buffered postcode layer from above in conjunction with each of the six GeoSure hazard grids (25m pixel size). This process considers each hazard in turn and calculates the average of the pixel values that occur within each of the buffered postcodes (circular areas). As each pixel covers the same area the resultant average represents the area-weighted average of the hazard values within the circular area. These average values for each hazard are added to the output Derived Postcode Database as 'occurrence factors'. 4. The six hazard occurrence factors for each postcode are summed and added to the DPD as column Total_of (Postcode Total Occurrence Factor, PTOF). 5. The Total_of column is classified into 5 classes divided into 5 equal categories as shown in table 3 of the newGeoSure Insurance Product: Methodology report. (IR/12/074). This classification is added as column Class5 with values of 1-10. This, and the Class5 split, is done in order to allow easier interpretation and visualisation of the total hazard if required (for example, Class5 can be used to colour up the postcode centroid in the GIS to show how the total hazard varies across an area).
publication
2011
false
See the referenced specification
publication
2010-12-08
false
See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF
Map Info File
Current BGS version
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.
British Geological Survey
Environmental Science Centre,Keyworth
NOTTINGHAM
NG12 5GG
United Kingdom
+44 115 936 3100
+44 115 936 3276
distributor
British Geological Survey
Environmental Science Centre,Keyworth
NOTTINGHAM
NG12 5GG
United Kingdom
+44 115 936 3100
pointOfContact
British Geological Survey
The Lyell Centre, Research Avenue South
EDINBURGH
EH14 4AP
United Kingdom
+44 131 667 1000
pointOfContact
2020-06-15