This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 24 June 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 25/04/2024 (Previous release) | Count on 06/06/2024 (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 5 minor errors were detected, of which 2 have existed since the previous refresh. All errors detected are considered to be minor. We aim to have all 5 errors resolved prior to the next release as part of ongoing quality improvements.
The next release of OS MasterMap Topography Layer is scheduled for 12 August 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) |
|---|---|
Total Feature Count
508 329 170
508 882 836
Count of Topo Area
127 146 339
127 289 166
Count of Topo Line
350 253 247
350 655 720
Count of Topo Point
4 385 721
4 388 037
Count of Topo Bline
532 257
531 327
Count of Topo CartoSym
3 788 842
3 789 871
Count of Topo CartoTxt
22 222 764
22 228 715
Total Count of Deletes
387 625
602 375
Count of Topo Area deletions
78 038
119 554
Count of Topo Line deletions
277 326
449 655
Count of Topo Point deletions
3 039
2 553
Count of Topo Bline deletions
533
1 350
Count of Topo CartoSymcc deletions
6 393
4 460
Count of Topo CartoTxtcc deletions
22 296
24 803
Total Count of Inserts
837 247
1 156 041
Count of Topo Area inserts
189 219
262 381
Count of Topo Line inserts
587 842
852 128
Count of Topo Point inserts
13 345
4 869
Count of Topo Bline inserts
218
420
Count of Topo CartoSym inserts
17 235
5 489
Count of Topo CartoTxt inserts
29 388
30 754
Total Count of Modifications
736 646
1 181 874
Count of Topo Area Modifications
369 267
601 058
Count of Topo Line Modifications
353 690
563 973
Count of Topo Point Modifications
231
220
Count of Topo Bline Modifications
2 681
2 947
Count of Topo CartoSym Modifications
44
46
Count of Topo CartoTxt Modifications
10 733
13 630
COU Size (bytes)
333 062 363
507 742 477
osgb1000000828071143
283459.15, 558287.03
osgb1000032166978
420041.3, 420633.65
osgb1000002023902176
570547.2, 321617.6
osgb1000000051338601
400106.45, 867491.455
osgb5000005222007891
334818.55, 415223.62
osgb1000001792732699
516068.135, 172721.936
Geographic area
Minimum area size for land cover
Minimum width
Urban
0.1hectares (ha) (1 000m²)
5m
Rural
0.1hectares (ha) (1 000m²)
10m
Mountain and moorland
1.0hectares (ha) (10 000m²)
10m
Geographic area
Minimum area size for land cover
Minimum width
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
