OS Large Scale Maps

General

The Ordnance Map is the base map for the cadastral map under section 11(6) of the 2012 Act. Currently, the base map used by Registers of Scotland in the Plan Creator is the OS MasterMap Topography Layer product, which is supplied to us in 3 scales - 1:1250, 1:2500 & 1:10,000.

Basic principles of MasterMap Topography Layer

The basic principles as stated by the OS are

• OS MasterMap is a digital vector map and represents the real world as series of points, lines and polygons

• Each feature has associated geometry; this may be the co-ordinates of a single point for a symbol representing a mile post alongside a road, or two pairs of co-ordinates representing each end of a straight fence, or 17 pairs of co-ordinates representing an irregularly shaped building polygon.

• Each feature has associated attributes that give information about the feature such as its geometry, its real-world classification (road, building, fence, etc), and its unique identity.

• OS MasterMap is positioned on the British National Grid, allowing the use of National Grid co-ordinates to locate features.

• OS MasterMap is captured at a base scale that is appropriate to the density of features in that area - 1:1250, 1:2500 & 1:10,000.

All the co-ordinates used in the MasterMap Topography Layer supplied to RoS are 2-dimensional and are based on the National Grid co-ordinate system i.e. easting and northings. The 3rd dimension, height, is not used by RoS at this time.