This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 12 August 2024.
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 06/06/2024 (Previous release) | Count on 25/07/2024 (Current release) |
|---|---|---|
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:
In this release 23 errors were detected of which 2 have existed since the previous refresh. These are all considered to be minor errors and there are no major errors present.
We aim to have all errors resolved prior to the next release as part of ongoing quality improvements.
The next release of OS MasterMap Topography Layer is scheduled for 23 September 2024.
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.
| TOID | Location (i.e. XY coordinates) |
|---|---|
| Geographic area | Minimum area size for land cover | Minimum width |
|---|---|---|
| Geographic area | Minimum area size for land cover | Minimum width |
|---|---|---|
Total Feature Count
508 882 836
509 529 397
Count of Topo Area
127 289 166
127 455 397
Count of Topo Line
350 655 720
351 126 174
Count of Topo Point
4 388 037
4 388 827
Count of Topo Bline
531 327
530 617
Count of Topo CartoSym
3 789 871
3 788 942
Count of Topo CartoTxt
22 228 715
22 239 440
Total Count of Deletes
602 375
636 733
Count of Topo Area deletions
119 554
129 723
Count of Topo Line deletions
449 655
478 982
Count of Topo Point deletions
2 553
2 227
Count of Topo Bline deletions
1 350
1 374
Count of Topo CartoSymcc deletions
4 460
4 265
Count of Topo CartoTxtcc deletions
24 803
20 162
Total Count of Inserts
1 156 041
1 283 294
Count of Topo Area inserts
262 381
295 954
Count of Topo Line inserts
852 128
949 436
Count of Topo Point inserts
4 869
3 017
Count of Topo Bline inserts
420
664
Count of Topo CartoSym inserts
5 489
3 336
Count of Topo CartoTxt inserts
30 754
30 887
Total Count of Modifications
1 181 874
1 213 405
Count of Topo Area Modifications
601 058
611 739
Count of Topo Line Modifications
563 973
585 817
Count of Topo Point Modifications
220
256
Count of Topo Bline Modifications
2 947
1 485
Count of Topo CartoSym Modifications
46
51
Count of Topo CartoTxt Modifications
13 630
14 057
COU Size (bytes)
507 742 477
539 082 200
osgb5000005333761759
266379.141, 661146.076
osgb1000002102169148
330922.334, 436520.256
osgb1000001792521555
514257.13, 177195.224
osgb1000000390862765
181610.432, 697265.48
osgb1000002031686162
377705.95, 414622.45
osgb5000005127065768
563861.53, 189432.44
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*
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
