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May 2024
This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 13 May 2024.
OSMM Topography Layer product count
The following table contains product counts for this release of OSMM Topography Layer data. The dates shown are extraction dates, not release dates.
Total Feature Count
507 879 548
508 329 170
Count of Topo Area
127 035 158
127 146 339
Count of Topo Line
349 942 731
350 253 247
Count of Topo Point
4 375 415
4 385 721
Count of Topo Bline
532 572
532 257
Count of Topo CartoSym
3 778 000
3 788 842
Count of Topo CartoTxt
22 215 672
22 222 764
Total Count of Deletes
363 259
387 625
Count of Topo Area deletions
75 296
78 038
Count of Topo Line deletions
253 444
277 326
Count of Topo Point deletions
4 059
3 039
Count of Topo Bline deletions
561
533
Count of Topo CartoSymcc deletions
8 953
6 393
Count of Topo CartoTxtcc deletions
20 946
22 296
Total Count of Inserts
866 957
837 247
Count of Topo Area inserts
198 781
189 219
Count of Topo Line inserts
595 718
587 842
Count of Topo Point inserts
17 417
13 345
Count of Topo Bline inserts
222
218
Count of Topo CartoSym inserts
23 256
17 235
Count of Topo CartoTxt inserts
31 563
29 388
Total Count of Modifications
634 202
736 646
Count of Topo Area Modifications
309 690
369 267
Count of Topo Line Modifications
308 659
353 690
Count of Topo Point Modifications
311
231
Count of Topo Bline Modifications
1 403
2 681
Count of Topo CartoSym Modifications
40
44
Count of Topo CartoTxt Modifications
14 099
10 733
COU Size (bytes)
336 114 289
333 062 363
Discrepancies
In this release 10 minor errors were detected, of which 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.
Land cover refinement changes
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:
Old land cover specification
Urban
0.1hectares (ha) (1 000m²)
5m
Rural
0.1hectares (ha) (1 000m²)
10m
Mountain and moorland
1.0hectares (ha) (10 000m²)
10m
New land cover specification
Urban
0.1hectares (ha) (1 000m²)
5m
Rural
0.1hectares (ha) (1 000m²)
5m*
Mountain and moorland
0.1hectares (ha) (1 000m²)*
5m*
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.
Changed TOIDs
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:
osgb1000000182286603
339097.4, 551740.35
osgb5000005285000934
459029.88, 402617.33
osgb1000002318155560
533464.054, 122925.909
osgb1000000302327200
207276.41, 691450.97
osgb5000005297224912
430701.235, 346985.231
osgb1000002081333910
596419.64, 208356.555
Next release
The next release of OS MasterMap Topography Layer is scheduled for 24 June 2024.
Annex A: Rural land cover specification refinement examples
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.
Example one
Location of example area one:
NS4505
NS 47825 05240
247790.7, 605224.0
TOIDs for example area one:
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):
Example two
Location of example area two:
NX3540
NX 37464 41871
237419, 541979
TOIDs for example area two:
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):
Example three
Location of example area three:
NX6550
NX 68975 51146
268968, 551139
TOIDs for example area three:
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):
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