Positional accuracy improvement programme

Programme

The month of data release is provided via the links below. In the case of rural towns the information is detailed by rural town name and in the case of rural areas the information is detailed by 1:10 000 block e.g. NN21.

Other rural areas*

Rural towns

As the programme has now completed the only relevant selection options are‘view all’ and ‘already released’.

PAI Availability within OS MasterMap^®

Customers should be aware of the fact that PAI data delivery in OS MasterMap Topo layer is different from Land-Line and this affects both the way the data is supplied and PAI completion dates.

The release of PAI data into OSMasterMap Topo layer follows release into Land-Line. PAI in Land-Line completed 31 March 2006 and at present our best estimate for completion in OS MasterMap Topo layer is 31 May 2006. The Programme Maps made available on this site relate to Land-Line PAI release only. For this reason information is included here about the current status of PAI in OS MasterMap Topo layer. The information is provided in an Excel spreadsheet containing three worksheets. These will be updated immediately after the refresh of the OSMasterMap Topo layer - see here our current planned schedule of refresh dates, and include the following:

List of blocks fully loaded
List of blocks partially loaded + list of tiles that have failed load and need to be resubmitted
Rural towns status - Loaded, not loaded yet + blocks supplied to date that include rural town detail.

OS MasterMap PAI Status 2nd October 2006 release* (148 Kb)

For those wishing to represent this graphically within their GI system, the table of tiles available in OSMasterMap is provided in three formats:

MID/MIF (4.83 Mb) *

Shape (6.35 Mb) *

Text (1.89 Mb) *

*Contains updates up to 21st September 2006.

PAI map tile listing

The map tiles that are affected by the PAI programme are all those that contain data surveyed at 1:2500 accuracy. This covers all maps with a 1 km by 1 km format reference, for example, SU3311. Some maps with a 500 m by 500 m format reference contain 1:2500 accuracy data only, for example, SU3313SW, or contain a mixture of both 1:1250 and 1:2500 accuracy, for example, SU3313SE. These are all included in the PAI programme.

To enable easy identification of PAI map tiles, this text file contains the reference numbers for all PAI map tiles (DMU), together with the xy co ordinates of the south west and north east corners of the map tile. The block in which the map tile is located is also listed. This can be imported into a GIS to display the PAI programme graphically.

The listing contains map tiles affected by both the Rural Towns and Other Rural Areas programmes, including those map tiles that have already been improved and released.

As the PAI programme progresses, amendments may be made to this listing. Any updates to the listing will be signified by a file name version and date increment.

PAI map tile listing v3.0 Aug 05 (1.1Mb zipped archive)

To enable easier identification of the DMUs included in the Rural Towns and Other Rural Areas programmes, the information in the text file PAI map tile listing v2.0 June04 has been split into the respective programmes. Each text file contains the reference numbers for the map tiles (DMU), together with the xy co-ordinates of the south west and north east corners of the map tile. The Rural Towns text file also contains the names of the towns.

Rural Areas map tile listing v3.0 Aug 05 (1.2Mb zipped archive)

Rural Towns map tile listing v2.0 July04 (24 Kb zipped archive)

Early release PAI

Some isolated quality issues were found in the early release of PAI data. The tiles under review were those captured under a survey programme that was run during Ordnance Survey's 2001/02 production year. All customers possibly affected have already been informed and have been party to ongoing consultation. Unless your organisation has already received correspondence about this Early Release data it is unlikely that you are affected. See here for further information on the remedial work to correct the issues.

PAI only - Reduced Real World Change

Due to poor flying conditions in 2005 it was not possible to capture all the imagery required to undertake full change and PAI update. A relatively small amount of PAI was undertaken using imagery previously captured but consequently not all the real would change could be included.

Further information on reduced RWC, including a programme of blocks affected is available.