The black outline represents geographical limit of the Greater London Authority (GLA). Areas in white represent tidal waters of the River Thames.
The London Region Atlas (LRA) covers a rectangular area of 80 x 62 km, from British National Grid coordinates: Easting 490 000 to 570 000 and Northing 153 000 to 215 000. The LRA was produced using the London Region Dataset (LRD, n=8400), created from two geochemical surveys (LOND and SEEN) carried out by the Geochemical Baseline Survey of the Environment (G-BASE) project during 2008 and 2009 for LOND, and from 2005 to 2009 for SEEN. The LOND survey is an urban soil geochemical survey based on 6801 sampling sites, 93% of which are located within the GLA, at a sampling density of 1 per 0.25 km2. SEEN is a south-east England rural soil survey done at a sampling density of 1 per 2 km2. A total of 1599 of the SEEN samples are included in the LRA area. As these are rural samples, 95% of them are outwith the GLA limit.