1:25 000 Scale Colour Raster

Specification

1:25 000 Scale Colour Raster

Coverage

Great Britain (England, Scotland and Wales)

Availability

Order by:

•         national extent (GB).
•         country extent: (England, Scotland and Wales).
•         individual tile.
•         user defined area.
•         specific tile identities; or
•         administrative region.

Tiles are supplied whole and not clipped.

Data source

Explorer production data.

Data structure

Raster.

Scale

Nominal scale is 1:25 000.

Recommended minimum to maximum scale range for viewing is 1:8000 to 1:25 000 scale.

It is best viewed between 1:10 000 and 1:15 000 scale

Transfer format

• TIFF 8 bit LZW compressed
• TIFF packbit compressed

Colour Options

• Colour

1:25 000 Scale Colour Raster data consists of a palette of 256 colours.

A high-quality alternative to black and white raster data is to use a Geographical Information System (GIS) to convert the colour data to a greyscale format.

Storage volume per tile

• Compressed: 1.5 Mb –3 Mb

Tile size

10 km by 10 km

Number of tiles in Great Britain

Great Britain  = 2 864 (edgematched)

• England: 1 508
• Wales: 289
• Scotland: 1 132

Supply media

CD and DVD

Resolution

254 dots per inch = 100 dots per cm

Update frequency

Change only update every six months after initial supply.

Usually issued in May and November.

Re-supply is available on request but may attract an additional charge.

Styling

A legend is available as a downloadable PDF file.

View or download a PDF version of the legend (1.68Mb)

Geo-reference files

To locate 1:25 000 Scale Colour Raster data tiles in their correct geographical position in a GIS they need to be 'georeferenced'.

More information and download the files

Coordinate Reference System

British National Grid (OSGB36).