Zmarties

The UK has probably the best national mapping service in the world, in the form of the Ordnance Survey. Their mapping data is used for almost all maps produced in the UK, and UK locations are normally specified using a National Grid Reference - which overlays a grid based on the metric system over the UK.

Google maps is different, even in its UK incarnation - its coordinate system is the universal latitude and longitude, which applies worldwide. The widespread use of GPS has also pushed latitude and longitude to the fore as an everyday system.

Thus there is an increasing need to convert from NGR data to lat/long data, and a few resources which can help are:

• detailed mathematical explanation from Ordnance Survey
• Wikipedia entry

There is ready written code available to do the conversion in

• perl
  
• javascript
• java
  

UK postal addresses also have postcodes, which might similarly be converted to latitude / logitude locations. Resources to help with that are:

• UK Postcodes