1:25 000 Scale Colour Raster is derived from the source data used to create its graphic counterpart, the OS Explorer Map series. Generalisation is used to emphasise, simplify, select and sometimes omit features to produce a cartographic representation of the landscape at a scale of 1:25 000.
The nominal scale of the product is 1:25 000, but the recommended minimum-to-maximum scale range is 1:8 000 to 1:25 000 scale.
1:25 000 Scale Colour Raster is available in National Grid coordinates, which are expressed in metres relative to an origin set to a point west of the Isles of Scilly. These coordinates can easily be spatially related to other surveys, drawings, datasets or Ordnance Survey products. A general introductory guide to the British National Grid (BNG) is available on the Ordnance Survey website.
Coverage is Great Britain only. 1:25 000 Scale Colour Raster is supplied in standard 10 km by 10 km tiles aligned to the National Grid.
1:25 000 Scale Colour Raster is updated via a revision programme. The revision programme mirrors that of the OS Explorer Map series, and is determined by assessing the following factors:
Known surveyed change
Change intelligence gathered from a range of sources
How long it's been since an area was last revised
Priority is given to prestige sites categorised as significant items of change, such as major road construction projects. Significant items of surveyed change relevant to the scale are captured during the revision programme.
Where a line feature ends by intersecting the tile edge, it is matched with its corresponding feature on the adjacent tile so that both features end on the same unique coordinate. The representation of detail across the tile edge will be of a cartographically acceptable standard when plotted or displayed at scale.
1:25 000 Scale Colour Raster is supplied to customers quarterly in March, June, September and December, incorporating any updates made by the revision programme.
This page details the features depicted in the 1:25 000 Scale Colour Raster.
Buildings are generalised and shown with colour tint and cartographically placed text to indicate settlement name and extent.
Structures are indicated by lines, buildings or symbols, and selected distinctive named features are supplemented with a text description.
Transport features depicted include tracks, paths, roads, railway lines (single and multiple track), railway stations, airports and airstrips, ferry routes and ports, cycle routes, and bus and coach stations.
Water features are shown in blue with associated text. A distinction is made between natural (blue) and man-made (black) water features, except for canals (which are shown in blue).
Different types of natural features and vegetation are shown by symbols or colour tint, including woods, rock, scree, boulders, sand, shingle, mud and slope.
The following routes are depicted in this product:
Footpaths, including permissive
Bridleways, including permissive
Byways open to all traffic
Restricted byways
Other routes with public access (ORPA)
National Trails and Scottish Great Trails and Recreational Routes
Recreational routes
Rights of way (England and Wales only)
Access land
Portrayal of access land is intended as a guide to land that is normally available for access on foot, for example, access land created under the Countryside and Rights of Way Act 2000, and land managed by The National Trust™, Woodland Trust, National Parks and local authorities. Land owned by Forestry England is only shown as Open Access where coincident with CRoW land.
Ground contours, survey heights and air survey heights are depicted. Heights are to the nearest metre above mean sea level. Heights shown close to a triangulation pillar refer to the ground level height at the pillar and not necessarily the height at the summit.
National, county, district, unitary authority and civil parish boundaries are all depicted in the product.
Selected tourist and leisure information is normally restricted to features providing public access or services. Tourist information is shown by a blue symbol using, where possible, nationally recognised symbols. Where appropriate, symbols also have black distinctive names, for example, country parks, major gardens and so on.
Depiction includes information supplied by English Heritage®, the Royal Commission on the Ancient and Historical Monuments of Scotland, and the Royal Commission on the Ancient and Historical Monuments of Wales.
Low and high water, man-made and natural landscape features are all depicted.
National Grid lines are shown at 1-km intervals.
Descriptive and distinctive names are depicted as text.
This document contains additional theoretical information related to 1:25 000 Scale Colour Raster. All users will find the Product Information document useful and informative.
The 1:25 000 Scale Colour Raster data product mirrors the popular OS Explorer Map series, showing a detailed overview of environmental and leisure features across Great Britain. It can provide the ideal mapping backdrop upon which to overlay business information. The 1:25 000 Scale Colour Raster’s backdrop can then be overlaid with other Ordnance Survey vector products or a customer’s own geographic / business data; it can also provide a useful background map in its own right.
Screen images can be plotted to produce a high-quality map. An example of the data is shown below.
1:25 000 Scale Colour Raster is aimed at professional / business markets and its graphic specification can aid with the following:
Environmental applications
Leisure applications
Construction
Engineering
Planning and licence applications
Farm / estate / property management
Real estate
Georeferencing is not required when using the GeoTIFF file format as the tiles have already been embedded with georeferencing information.
To be able to view each TIFF tile in correct geographic relation to the National Grid and to other tiles, the tiles must be georeferenced. Geographic information systems (GIS) typically provide georeferencing as part of their functionality, but for each set of tiles, it is necessary to provide the information on how the tiles should be ordered.
Ordnance Survey provides this information in a set of georeferencing files, also known as world files. A complete set of georeferencing files for 1:25 000 Scale Colour Raster is available on the .
There are several different types of world file. Prior to downloading one of the sets, customers are advised to check with their system suppliers to find out which type of world file their system supports.
The conventions behind the files’ creation can be found in the . By using the conventions outlined there, this means that other datasets using the same conventions can be imported into the same GIS to add value to the raster map; for example, overlaying a routing or logistics network over the map or displaying a customer’s demographic information.
The georeferencing files should be saved in the same directory as the files of the map tiles themselves.