August 2026
This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 03 August 2026.
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
518 716 931
519 342 087
Count of Topo Area
129 800 144
129 958 160
Count of Topo Line
357 689 858
358 140 859
Count of Topo Point
4 472 625
4 473 894
Count of Topo Bline
517 810
517 322
Count of Topo CartoSym
3 858 982
3 858 766
Count of Topo CartoTxt
22 377 512
22 393 086
Total Count of Deletes
554 031
756 720
Count of Topo Area deletions
107 977
143 937
Count of Topo Line deletions
407 755
565 880
Count of Topo Point deletions
1 801
2 577
Count of Topo Bline deletions
728
1 289
Count of Topo CartoSym deletions
2 767
4 306
Count of Topo CartoTxt deletions
33 033
38 731
Total Count of Inserts
1 097 001
1 381 876
Count of Topo Area inserts
246 877
301 953
Count of Topo Line inserts
795 103
1 016 881
Count of Topo Point inserts
2 744
3 846
Count of Topo Bline inserts
246
801
Count of Topo CartoSym inserts
2 240
4 090
Count of Topo CartoTxt inserts
49 791
54 305
Total Count of Modifications
2 919 560
2 087 450
Count of Topo Area Modifications
483 027
683 458
Count of Topo Line Modifications
2 408 940
1 381 302
Count of Topo Point Modifications
395
527
Count of Topo Bline Modifications
1 217
1 090
Count of Topo CartoSym Modifications
22
29
Count of Topo CartoTxt Modifications
25 959
21 044
COU Size (bytes)
552 968 192
579 604 480
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:
osgb1000000288707129
270982.824, 960152.554
osgb5000005336030861
236484.655, 206357.086
osgb1000000275442044
363684.85, 147552.82
osgb5000005271762130
244956.788, 949673.599
osgb5000005351687039
258258.382, 332031
osgb5000005352509485
530782.585, 259576.42
Discrepancies
In this release 0 errors were detected.
Next release
The next release of OS MasterMap Topography Layer is scheduled for 14 September 2026.
Last updated
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