November 2025
This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 24 November 2025.
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
515 614 618
516 255 739
Count of Topo Area
129 018 023
129 179 335
Count of Topo Line
355 475 070
355 932 638
Count of Topo Point
4 455 077
4 462 725
Count of Topo Bline
520 905
520 570
Count of Topo CartoSym
3 845 014
3 854 066
Count of Topo CartoTxt
22 300 529
22 306 405
Total Count of Deletes
727 014
836 866
Count of Topo Area deletions
135 551
162 006
Count of Topo Line deletions
530 546
612 392
Count of Topo Point deletions
6 315
6 892
Count of Topo Bline deletions
2 034
943
Count of Topo CartoSym deletions
7 229
5 155
Count of Topo CartoTxt deletions
45 339
49 478
Total Count of Inserts
1 366 855
1 477 987
Count of Topo Area inserts
296 253
323 318
Count of Topo Line inserts
986 399
1 069 960
Count of Topo Point inserts
18 654
14 540
Count of Topo Bline inserts
605
608
Count of Topo CartoSym inserts
19 475
14 207
Count of Topo CartoTxt inserts
45 474
55 354
Total Count of Modifications
1 274 983
1 407 831
Count of Topo Area Modifications
635 899
715 622
Count of Topo Line Modifications
620 168
673 769
Count of Topo Point Modifications
1 177
1 110
Count of Topo Bline Modifications
2 063
1 450
Count of Topo CartoSym Modifications
66
54
Count of Topo CartoTxt Modifications
15 610
15 826
COU Size (bytes)
511 583 092
625 627 136
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:
osgb5000005333266045
329288.91, 667878.807
osgb5000005225411653
335284.33, 445332.88
osgb5000005316042299
615133.243, 305804.265
osgb5000005324924136
140963.498, 831364.515
osgb1000000222715645
322651.151, 476807.838
osgb5000005200470167
584183.128, 345730.459
Discrepancies
In this release 25 errors were detected, of which 25 are new errors. 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.
Next release
The next release of OS MasterMap Topography Layer is scheduled for 05 January 2026.
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