May 2024
This release note provides information about the latest release of OS MasterMap (OSMM) Topography Layer, released to customers on 13th 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.
OSMM Topography Layer | Count on 14/03/2024 (Current release) | Count on 25/04/2024 (Current release) |
---|---|---|
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
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.
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) |
---|---|
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 24th 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 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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