This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 16 February 2026.
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
516 731 189
517 279 866
Count of Topo Area
520 602
520 431
Count of Topo Line
3 859 375
3 859 805
Count of Topo Point
22 311 817
22 327 375
Count of Topo Bline
129 299 175
129 436 199
Count of Topo CartoSym
356 273 836
356 666 805
Count of Topo CartoTxt
4 466 384
4 469 251
Total Count of Deletes
598 529
678 764
Count of Topo Area deletions
281
527
Count of Topo Line deletions
2 984
2 983
Count of Topo Point deletions
38 622
44 436
Count of Topo Bline deletions
113 839
134 834
Count of Topo CartoSym deletions
437 808
492 827
Count of Topo CartoTxt deletions
4 995
3 157
Total Count of Inserts
1 073 979
1 227 441
Count of Topo Area inserts
313
356
Count of Topo Line inserts
8 293
3 413
Count of Topo Point inserts
44 034
59 994
Count of Topo Bline inserts
233 679
271 858
Count of Topo CartoSym inserts
779 006
885 796
Count of Topo CartoTxt inserts
8 654
6 024
Total Count of Modifications
1 038 366
1 158 022
Count of Topo Area Modifications
404
611
Count of Topo Line Modifications
151
32
Count of Topo Point Modifications
12 494
17 051
Count of Topo Bline Modifications
527 931
590 892
Count of Topo CartoSym Modifications
496 225
549 034
Count of Topo CartoTxt Modifications
1 161
402
COU Size (bytes)
464 904 192
514 400 256
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:
osgb1000000288795323
238523.656 921440.485
osgb1000034193828
271625.8 331824.9
osgb1000000083109971
495166.8 484212.1
osgb1000000288009704
203104.4 907457.1
osgb1000002092953297
276099.423 207624.585
osgb5000005243347366
393168.73 459052.754
In this release 40 errors were detected, of which, 15 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 30 March 2026.
Last updated
Was this helpful?
Was this helpful?
