This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 02 April 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 01/02/2024 (Previous release) | Count on 14/03/2024 (Current release) |
|---|---|---|
9 minor errors were detected, which is 2 more than were found in the last refresh. Of these 9 errors, 2 have existed since the previous refresh. All errors are considered to be minor errors. We aim to have all errors resolved prior to the next release as part of ongoing quality improvement.
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 13 May 2024.
| Geographic area | Minimum area size for land cover | Minimum width |
|---|---|---|
| Geographic area | Minimum area size for land cover | Minimum width |
|---|---|---|
Total Feature Count
507 375 850
507 879 548
Count of Topo Area
126 911 673
127 035 158
Count of Topo Line
349 600 457
349 942 731
Count of Topo Point
4 362 057
4 375 415
Count of Topo Bline
532 911
532 572
Count of Topo CartoSym
3 763 697
3 778 000
Count of Topo CartoTxt
22 205 055
22 215 672
Total Count of Deletes
352 971
363 259
Count of Topo Area deletions
72 340
75 296
Count of Topo Line deletions
246 393
253 444
Count of Topo Point deletions
4 698
4 059
Count of Topo Bline deletions
433
561
Count of Topo CartoSymcc deletions
11 208
8 953
Count of Topo CartoTxtcc deletions
17 899
20 946
Total Count of Inserts
811 142
866 957
Count of Topo Area inserts
180 007
198 781
Count of Topo Line inserts
551 663
595 718
Count of Topo Point inserts
21 692
17 417
Count of Topo Bline inserts
353
222
Count of Topo CartoSym inserts
29 505
23 256
Count of Topo CartoTxt inserts
27 922
31 563
Total Count of Modifications
600 677
634 202
Count of Topo Area Modifications
294 892
309 690
Count of Topo Line Modifications
291 597
308 659
Count of Topo Point Modifications
326
311
Count of Topo Bline Modifications
628
1 403
Count of Topo CartoSym Modifications
132
40
Count of Topo CartoTxt Modifications
13 102
14 099
COU Size (bytes)
386 470 897
336 114 289
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*
TOID
Location (i.e. XY coordinates)
osgb5000005109728428
322926.508, 704955.071
oosgb5000005252408974
396225, 4754643
osgb1000000030598131
504443.618, 242017.376
osgb1000000293839535
203531.7, 862031.28
osgb5000005299999425
406660.07, 436264.33
osgb5000005243520249
505688.732, 484331.45
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
