# 1:250 000 Scale Colour Raster Technical Specification

## 1:250 000 Scale Colour Raster product specification

### Number of tiles in Great Bitain

56 (edge matched)

### Tile size

100km by 100km

### Coverage

Great Britain

### Availability

National coverage (in a single download)

### Resolution

254 dots per inch (dpi)

### Data structure

Raster

### Storage volumes (Great Britain coverage)

* 128 MB (compressed)
* 130 MB (uncompressed)

### Update frequency

Quarterly: Annually (June)

## Product legend <a href="#bookmark1" id="bookmark1"></a>

Maintained versions (in English and Welsh) of the 1:250 000 Scale Colour Raster legend, which defines all of the map symbols used in the product, can be found on the [1:250 000 Scale Colour Raster Downloads page.](/os-downloads/products/maps-and-imagery-portfolio/1-250-000-scale-colour-raster/1-250-000-scale-colour-raster-downloads.md)

## Gazetteer <a href="#bookmark2" id="bookmark2"></a>

The 1:250 000 Scale Gazetteer includes approximately 25 500 points that cover the extent of the 56 100km by 100km tiles. The information is provided as a single file in ASCII text format and is included in the compressed download file.

## Additional technical information

Additional information, common to all colour raster map products is available through the Colour Raster Map Fundamental pages. These pages provide an overview of the product and a technical specification covering:

* [Georeferencing](/os-downloads/products/maps-and-imagery-portfolio/maps-and-imagery-fundamentals/maps-and-imagery-products-technical-specification/georeferencing.md)
* [Image file directory (TIFF)](/os-downloads/products/maps-and-imagery-portfolio/maps-and-imagery-fundamentals/maps-and-imagery-products-technical-specification/image-file-directory-tiff.md)
* [Product glossary](/os-downloads/products/maps-and-imagery-portfolio/maps-and-imagery-fundamentals/maps-and-imagery-products-technical-specification/product-glossary.md)


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