August 2024
This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 12th August 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.
OSMM Topography Layer | Count on 06/06/2024 (Previous release) | Count on 25/07/2024 (Current release) |
---|---|---|
Total Feature Count | 508 882 836 | 509 529 397 |
Count of Topo Area | 127 289 166 | 127 455 397 |
Count of Topo Line | 350 655 720 | 351 126 174 |
Count of Topo Point | 4 388 037 | 4 388 827 |
Count of Topo Bline | 531 327 | 530 617 |
Count of Topo CartoSym | 3 789 871 | 3 788 942 |
Count of Topo CartoTxt | 22 228 715 | 22 239 440 |
Total Count of Deletes | 602 375 | 636 733 |
Count of Topo Area deletions | 119 554 | 129 723 |
Count of Topo Line deletions | 449 655 | 478 982 |
Count of Topo Point deletions | 2 553 | 2 227 |
Count of Topo Bline deletions | 1 350 | 1 374 |
Count of Topo CartoSymcc deletions | 4 460 | 4 265 |
Count of Topo CartoTxtcc deletions | 24 803 | 20 162 |
Total Count of Inserts | 1 156 041 | 1 283 294 |
Count of Topo Area inserts | 262 381 | 295 954 |
Count of Topo Line inserts | 852 128 | 949 436 |
Count of Topo Point inserts | 4 869 | 3 017 |
Count of Topo Bline inserts | 420 | 664 |
Count of Topo CartoSym inserts | 5 489 | 3 336 |
Count of Topo CartoTxt inserts | 30 754 | 30 887 |
Total Count of Modifications | 1 181 874 | 1 213 405 |
Count of Topo Area Modifications | 601 058 | 611 739 |
Count of Topo Line Modifications | 563 973 | 585 817 |
Count of Topo Point Modifications | 220 | 256 |
Count of Topo Bline Modifications | 2 947 | 1 485 |
Count of Topo CartoSym Modifications | 46 | 51 |
Count of Topo CartoTxt Modifications | 13 630 | 14 057 |
COU Size (bytes) | 507 742 477 | 539 082 200 |
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:
TOID | Location (i.e. XY coordinates) |
---|---|
osgb5000005333761759 | 266379.141, 661146.076 |
osgb1000002102169148 | 330922.334, 436520.256 |
osgb1000001792521555 | 514257.13, 177195.224 |
osgb1000000390862765 | 181610.432, 697265.48 |
osgb1000002031686162 | 377705.95, 414622.45 |
osgb5000005127065768 | 563861.53, 189432.44 |
Discrepancies
In this release 23 errors were detected of which 2 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.
Next release
The next release of OS MasterMap Topography Layer is scheduled for 23rd September 2024.
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
Geographic area | Minimum area size for land cover | Minimum width |
---|---|---|
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
Geographic area | Minimum area size for land cover | Minimum width |
---|---|---|
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.
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 one.
5km tile | OS grid reference | Coordinates (OSGB36) |
NS4505 | NS 47825 05240 | 247790.7 605224.0 |
TOIDs for example one.
OSMM Topography Layer (July 2022) | OSMM Topography Layer (August 2022) |
osgb1000000316775097 | 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 two.
5km tile | OS grid reference | Coordinates (OSGB36) |
NX3540 | NX 37464 41871 | 237419, 541979 |
TOIDs for example two.
OSMM Topography Layer (August 2022) | OSMM Topography Layer (October 2022) |
osgb1000000318639911 | 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 three.
5km tile | OS grid reference | Coordinates (OSGB36) |
NX6550 | NX 68975 51146 | 268968, 551139 |
TOIDs for example three.
OSMM Topography Layer (August 2022) | OSMM Topography Layer (October 2022) |
osgb1000000319079420 | 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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