The GIS Base Table links the unit postcodes with the Ordnance Survey 100m grid references (Easting/Northing). This gives the user the ability to calculate distances between postcodes and, therefore, to determine "nearest to". Additionally, this table can be extended to include Post Towns, which will provide the flexibility to derive distances between, for instance, a town and a postal sector. This involves a "centroid" calculation, although this sounds complex, all you do is average the eastings and northings for all postcodes within the required area.

GBT Lat/Long provides 2 additional fields containing the Latitude & Longitude coordinates which allows access to mapping services such as Google Maps via their global API. Below is a screen shot of of the first few records of the GBT Lat/Long Table sample, a CSV file imported into Excel. If you wish to try the data, there are downloads of both files to the right of this page.

File layouts for both the GIS Base Table and the GBT Lat/Long are available in PDF format from the downloads to the right. These documents also contain notes on both the content and use of these datasets. 

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