Ordnance Survey have created and continue to maintain the National Topographic Database. This Database is their record of the topographic features in Great Britain at any time. All of their map and data products are derived from this database. Ordnance Survey revise the database to reflect changes in the real world, and in doing so apply a series of priorities. For these priorities, Ordnance Survey categorise change into 4 different categories. The table below describe these categories.
| What it includes | OS revision policy | |
|---|---|---|
| Category 1 |
|
Technique
|
| Category 2 | No longer used | |
| Category 3 |
|
Technique
|
| Category 4 |
|
Frequency
|
| Category 5 |
|
Frequency
|
| Ordnance Survey product | Roam View | Frequency of update | Date of creation of data currently within Digimap |
|---|---|---|---|
| Land-Line.Plus® | n/a | No longer updated | No longer available |
| OS MasterMap® Topography | Detailed and Plan | Annual | June 2010 |
| OS MasterMap® Topography and ITN in Data Download | n/a | Bi-annual | January 2011 |
| Meridian™2 | District | Annual | April 2010 |
| Land-Form PANORAMA™ | District | not updated | November 1993 |
| Land-Form PROFILE | n/a | Infrequent | August 2003 |
| 1:50,000 Colour Raster | Local | Annual | June 2010 |
| 1:25,000 Colour Raster | Neighbourhood | Annual | May 2010 |
| 1:10,000 Colour Raster | Street | Annual | June 2010 |
| 1:250,000 Colour Raster | n/a | Annual | May 2010 |
| MiniScale | County, Regional and National | Annual | January 2010 |
| Strategi® | Metropolitan and City | Annual | January 2010 |
| 1:50,000 Scale Gazetteer | n/a | Annual | June 2010 |
| Code-Point® with Polygons | Postcode Query | Annual | March 2010 |
| Boundary-Line™ | n/a | Annual | May 2010 |
| OS VectorMap™ Local | n/a | Annual | April 2010 |
| OS VectorMap™ District | n/a | Annual | March 2011 |
| OS Street View® | n/a | Annual | May 2010 |