Ordnance Survey (OS)

Great Britain's national mapping agency site contains sources and contacts for all the products OS produce and the services it provides. The site also contains the GIS Files - an interactive learning area, Get-a-map - a free Internet mapping service (OSview software can be downloaded in order to view the digital map data), information about OS MasterMap (the definitive digital map of Great Britain from which all new OS products are derived) and the National GPS Network, an online service to convert Global Positioning System longitude/latitude readings to the GB National Grid projection.
The site also contains free downloadable GB Coastline and Administrative boundary maps in a range of formats including EPS (vector); TIF (raster); PDF; GIF (raster) in addition to a variety of Election maps containing administrative and electoral boundaries that can be overlaid onto a base map.  The site also includes some Teaching Resources.

Spatial Coverage: 
United Kingdom
Format: 

EPS (vector); TIF (raster); PDF; GIF (raster)

Data Access: 

Freely available data on internet. Some data requires registration. Additionally commercial mapping products are available via payment.