OS Landplan^® Data

Frequently Asked Questions (FAQs)

Can I purchase the data with or without contours?

Yes, you can purchase the data with or without contours and in colour or monochrome.

How do I load the data?

Data is supplied as an image (raster) in TIFF 8-bit LZW compressed format.

LZW format – information about this file format can be found on the Unisys^® website. The patent and licence fees that formerly applied to this format have now expired, so it can be regarded as freeware. A link to the appropriate web page is  http://www.unisys.com/about__unisys/lzw

In case of difficulties opening the data in any software system, try removing the LZW compression by using the following methods:

1. Unisys www.unisys.com are able to provide the appropriate free software.
2. It is possible to remove the compression using imaging software, for example, Adobe^® Photoshop^®.

Note that the data will have a much larger volume when decompressed.

CAD software – most CAD software requires that the data is decompressed. Once decompressed it should be straightforward to open the data. Use 'Help' in your CAD software to gain more information about displaying a raster image.

Geographical information systems (GIS) – the data can be opened in GIS software. If you want to ascertain exact coordinates of points on the map, the data will need to be georeferenced to the corner points of the map. These coordinates are supplied with each site-centred data order, but the user needs to create their own georeferencing files for their GI software.

Imaging software (for example, Adobe Photoshop) – the data can be opened in any imaging software that supports the TIFF. Data can be viewed and sub-selected, for example, for use in reports, as required.

Can I georeference the data file?

If you need to georeference the data this can only be achieved in AutoCAD^® or a GIS and requires the user to create their own file. Virtually all GIS will read either a MapInfo^® TAB or an ESRI^® TFW world file. Both differ slightly in the way that they are set up, so the user needs to identify which system they can use.

Centre and corner coordinate information is included in a separate file with each data order, so a user does have the appropriate information to create their own georeference files.

I have bought a colour 1:10 000 scale raster data tile; can I convert it into a monochrome image?

It depends on which software package you are using. Some packages have a facility whereby you can load the colour image onto a computer and, using one of the command drop-down menus, select the greyscale option. This will change the colours on an image to shades of grey (greyscale). This is not the same output as monochrome where features in the file are either black or white.

I have bought the monochrome raster; can I convert this to colour?

No. You can change the black to another colour but there are only two colours (black and white) are supplied with this product option.

Why is the data only produced in TIFF LZW and not other formats?

This format conforms to the TIFF standard and can be read by a wide range of software.

Why use LZW?

LZW is one of the better (available at no charge) compression formats for use with our map data. It maintains the integrity of the data file when it is compressed/uncompressed where other formats may lose definition or resolution. This could cause files to degrade and result in areas of map information to be lost.

Can I distribute the data to clients/contractors or produce paper copies from the data?

You need to ensure that you have completed an end-user and/or a contractor licence. These are available from Ordnance Survey Mapping and Data Centres and give detailed information about what you are licensed to do.

Why is there a limit on the size of the area I can order?

The extent of area coverage available for OS Landplan Data is less than that available for OS Landplan Plots. The TIFF data files can become very large as the extent of area coverage increases, even when the data files are compressed.

An area limit of 25 km² has been set, which will generate file sizes of about 4Mb. Using email as a delivery service, some Internet Service Providers (ISP) may have set a limit less than this. Users should check the capacity that a provider has set.

Flexibility has been included with area coverage so that any combination of size can be ordered provided it does not exceed 25 km², for example, 1km x 25km or 3km x 8km.

Adobe and Photoshop are registered trademarks of Adobe Systems Incorporated. AutoCAD is a registered trademark of Autodesk Incorporated. ESRI is a registered trademark of Environmental Systems Research Institute, Inc. MapInfo is a registered trademark of MapInfo Corporation. Unisys is a registered trademark of Unisys Corporation.