This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 09 October 2023.
The following table contains product counts for this release of OSMM Topography Layer data. The dates shown are extraction dates, not release dates.
| OSMM Topography Layer | Count on 10/08/2023 (Previous Release) | Count on 21/09/2023 (Current Release) |
|---|---|---|
Alongside GML format, OSMM Topography Layer is also available in GeoPackage and vector tiles formats (from March 2023). Please see the Getting Started with GeoPackage and Getting Started with Vector Tiles guides for more information on using these new formats. The product is supplied as an online download. You can download data in its various formats from the OS Data Hub.
48 minor errors were detected, which is 12 more than the 36 errors found in the last refresh. Of these errors, 4 have existed since the previous refresh – these are minor issues caused by conflict (where the geometry of adjacent feature has not been updated to match), but there are no visible issues.
An issue has been identified whereby post offices are being incorrectly attributed or deleted due to data misinterpretation. In the previous release over 1 100 reclassified / deleted post offices were noted. There are 966 of these errors remaining in the October 2023 release. This may result in the carto text ‘Post Office’ or ‘PO’ missing from OSMM Topography Layer. A solution is currently being investigated for this issue and we aim to rectify it as soon as possible.
The land cover specification for rural geographies has been refined. The Mountain and Moorland refinement was completed in 2022.
The rural geography updates began capture in May 2022. The initial updates fed through to the July 2022 release of OSMM Topography Layer, with the multi class land cover polygons completed in December 2022. The single class land cover polygons will continue to feed through to product from April 2023.
The following two tables articulate this specification refinement:
The asterisk symbol (*) shows which criteria have been refined.
The land cover specification refinement means that the rural land cover data within OSMM Topography Layer will become more granular, producing a more detailed view made up of smaller more numerous polygons. This provides users with more accurate data that meets each individual’s specific requirements. These changes are purely refinements and do not change the data attribution.
Annex A shows three examples of how the rural land cover refinement is being translated into OSMM Topography Layer.
Numerous TOIDs (Topographic Identifiers) have changed since the last refresh, resulting in a visual difference in the data. The list below shows a sample of changed TOIDs and their locations that you can use as 'lookup samples' to validate that your latest supply has updated correctly:
The next release of OS MasterMap Topography Layer is scheduled for 20 November 2023.
| Geographic Area | Minimum Area Size for Land Cover | Minimum Width |
|---|---|---|
| Geographic Area | Minimum Area Size for Land Cover | Minimum Width |
|---|---|---|
| TOID | Location (i.e. XY coordinates) |
|---|---|
Total Feature Count
505 631 081
506 051 882
Count of Topo Area
126 426 540
126 561 435
Count of Topo Line
348 477 006
348 736 616
Count of Topo Point
4 311 133
4 321 409
Count of Topo Bline
534 114
533 621
Count of Topo CartoSym
3 712 020
3 722 356
Count of Topo CartoTxt
22 170 268
22 176 445
Total Count of Deletes
580 807
552 193
Count of Topo Area deletions
93 938
90 968
Count of Topo Line deletions
440 874
413 319
Count of Topo Point deletions
4 722
4 058
Count of Topo Bline deletions
689
1 023
Count of Topo CartoSymcc deletions
10 421
9 835
Count of Topo CartoTxtcc deletions
30 163
32 990
Total Count of Inserts
963 518
972 994
Count of Topo Area inserts
218 909
225 863
Count of Topo Line inserts
672 774
672 929
Count of Topo Point inserts
14 794
14 334
Count of Topo Bline inserts
296
530
Count of Topo CartoSym inserts
21 966
20 171
Count of Topo CartoTxt inserts
34 779
39 167
Total Count of Modifications
941 944
833 584
Count of Topo Area Modifications
442 081
378 432
Count of Topo Line Modifications
479 273
430 672
Count of Topo Point Modifications
339
319
Count of Topo Bline Modifications
665
1 190
Count of Topo CartoSym Modifications
173
103
Count of Topo CartoTxt Modifications
19 413
22 868
COU Size (bytes)
418 831 687
413 944 082
Urban
0.1hectares (ha) (1 000m²)
5m
Rural
0.1hectares (ha) (1 000m²)
10m
Mountain and moorland
1.0hectares (ha) (10 000m²)
10m
Urban
0.1hectares (ha) (1 000m²)
5m
Rural
0.1hectares (ha) (1 000m²)
5m*
Mountain and moorland
0.1hectares (ha) (1 000m²)*
5m*
osgb5000005305675906
266453.432, 660668.531
osgb5000005121024361
297913.54, 337342.3
osgb5000005141832094
530516.838, 268540.61
osgb1000000390737946
140986.634, 699762.657
osgb1000002312456023
271311.2, 318049.66
osgb5000005282543279
614730.487, 257892.756
Below are three real-world examples of how the rural land cover specification refinement has affected the data within OSMM Topography Layer. The examples showcase three areas in southern Scotland where the specification refinement has broken up one land polygon within the Topographic Area Feature Type into smaller, separate polygons.
OSMM Topography Layer (July 2022): osgb1000000316775097
OSMM Topography Layer (August 2022): osgb5000005297485451, osgb5000005297485455, osgb5000005297485456
Source imagery of example area one for comparative purposes:
Data before the rural land cover specification refinement update (OSMM Topography Layer – July 2022):
Data after the rural land cover specification refinement update (OSMM Topography Layer – August 2022):
OSMM Topography Layer (July 2022): osgb1000000318639911
OSMM Topography Layer (August 2022): osgb1000000318639911, osgb5000005298080383, osgb5000005298080465
Source imagery of example area two for comparative purposes:
Data before the rural land cover specification refinement update (OSMM Topography Layer – August 2022):
Data after the rural land cover specification refinement update (OSMM Topography Layer – October 2022):
OSMM Topography Layer (July 2022): osgb1000000319079420
OSMM Topography Layer (August 2022): osgb1000000319079420, osgb5000005298106224
Source imagery of example area three for comparative purposes:
Data before the rural land cover specification refinement update (OSMM Topography Layer – August 2022):
Data after the rural land cover specification refinement update (OSMM Topography Layer – October 2022):
| 5km Tile | OS Grid Reference | Coordinates (OSGB36) |
|---|---|---|
| 5km Tile | OS Grid Reference | Coordinates (OSGB36) |
|---|---|---|
| 5km Tile | OS Grid Reference | Coordinates (OSGB36) |
|---|---|---|
NS4505
NS 47825 05240
247790.7, 605224.0
NX3540
NX 37464 41871
237419, 541979
NX6550
NX 68975 51146
268968, 551139
