When only the most detailed site map will do the OS Mastermap® is the map of choice for block plans, site plans, and location plans at the largest scales. Use this for standard scales of 1:1250, 1:2500 and 1:500. They can also be used for super scales of 1:200 and 1:100.
OS Mastermap® is the intelligent digital map designed by Ordnance Survey for use in general business documents and with geographical information systems (GIS). Based on the National Grid, it includes topographic information on every landscape feature - buildings, roads, phone boxes, postboxes, landmarks - and represents a significant evolution from traditional cartography.
Streetwise Master map contains four combined layers - each made up of various mapping features. Each feature has its own unique identifier or TOID. This large scale mapping is therefore not only extremely detailed but also significantly more up-to-date than traditional maps.
Streetwise as an OS Platinum Partner is supplied with UK updates on a quarterly basis and so clients will always be able to view up-to-date mapping. As the OS says "Ordnance Survey is committed to providing businesses with the most reliable datasets in Great Britain. Combined with your own information, Ordnance Survey MasterMap® will always give the most detailed picture of your operational area."