1:25 000 Scale Colour Raster Technical Specification
This technical specification provides detailed technical information about 1:25 000 Scale Colour Raster. It is targeted at technical users and software developers.
The following pages contain information about 1:25 000 Scale Colour Raster, including file compression, legends, georeferencing and formats.
1:25 000 Scale Colour Raster Specification
Number of tiles in Great Britain
2,859 (edge matched)
England: 1,508
Scotland: 1,130
Wales: 289
Tile size
10 km by 10 km
Availability
National coverage
Resolution
254 and 660 dots per inch
Data structure
Raster
Transfer formats
TIFF PackBits compressed
TIFF palette 8-bit (256 colours) with LZW* compression
GeoTIFF with LZW* compression
* If LZW compressed formats are used, then registration may be required. Information is available on the Unisys® website.
Storage volumes per tile
0.2–9 Mb compressed
Update frequency
Quarterly: March, June, September and December (change-only updates)
Product legend
Maintained versions (in English and Welsh) of the 1:25 000 Scale Colour Raster legend, which defines all of the map symbols used in the product, can be found on the 1:25 000 Scale Colour Raster Product Support page of the OS website:
Common mapping abbreviations used in the product
A full list of the common mapping abbreviations used in 1:25 000 Scale Colour Raster is available on the OS website.
Index
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