Organised Editing/Activities/TomTom/Global - Building Height Imports/Japan - PLATEAU Building Height Enrichment
Overview
TomTom, in consultation with the Japanese OpenStreetMap community and stakeholders connected to Japan's Project PLATEAU initiative, is supporting a community-reviewed process to enrich existing OSM building footprints with missing height tags. The heights are derived from the Project PLATEAU 3D city model datasets published by Japan's Ministry of Land, Infrastructure, Transport and Tourism (MLIT). This activity is considered as complimentary to Japan's MLIT PLATEAU/imports.
This activity follows an import-style workflow with upfront community consultation, transparent documentation, conservative acceptance rules, and a staged rollout starting with a pilot area (Osaka City not Osaka Prefecture).
Context
Japan has strong building footprint coverage in OpenStreetMap, but many buildings still lack consistent height=* or building:levels=* tagging. Building heights have been a long-standing gap in Japanese OSM data. Project PLATEAU, a national digital twin initiative led by MLIT, now makes adding heights feasible at scale by providing open 3D city model datasets for approximately 250+ Japanese cities.
Adding reliable building heights enables:
- Better 3D map rendering and urban visualization
- Navigation context enrichment
- Urban planning and digital twin use cases
- Environmental modelling (e.g. flood risk, solar analysis)
- AR/VR and visualization applications
- Future quality benchmarking for Japanese building datasets
This effort is supported by TomTom, which has committed engineering and community resources, in consultation with the Japanese OSM community and Project PLATEAU / MLIT stakeholders. Similar building height imports have been completed in other countries (e.g. Netherlands — 3D BAG, Norway), and we hope to learn from those experiences. We welcome everyone to voice, contribute, review and challenge any part of this project.
Note: Parts of southern Osaka City already have building heights imported by community member okadatsuneo using PLATEAU data. These areas are automatically excluded from this process, as buildings with existing height=* tags are skipped by the acceptance rules described below.
Data Source
| Field | Details |
|---|---|
| Dataset | Project PLATEAU |
| Producer | Ministry of Land, Infrastructure, Transport and Tourism (MLIT), Japan |
| Source portal | https://front.geospatial.jp/plateau_portal_site/ |
| Formats available | CityGML, 3D Tiles, GeoJSON, MVT, GeoTIFF |
| Geographic coverage | Approximately 250+ Japanese cities |
| Building LOD coverage | LOD0, LOD1, LOD2, LOD3 |
| Key attributes | measuredHeight, storeysAboveGround, roof type, usage, hazard layers
|
| CRS (source) | EPSG:6697 |
| CRS (output) | EPSG:4326 |
The current process focuses primarily on CityGML building datasets.
License
| Field | Details |
|---|---|
| PLATEAU data license | Multi-license: CC BY 4.0 / ODbL / ODC-BY |
| Commercial use | Allowed |
| Attribution required | Yes |
| ODbL compatibility | Explicitly supported by PLATEAU terms |
| Source attribution | Ministry of Land, Infrastructure, Transport and Tourism (MLIT) |
PLATEAU explicitly permits use under ODbL-compatible workflows, including OpenStreetMap-related activities. Per the PLATEAU terms, attribution is provided in the changeset comment for every batch and on this wiki page.
Attribution example: Source: Project PLATEAU, Ministry of Land, Infrastructure, Transport and Tourism (MLIT)
Methodology — Building Height Extraction
The process parses CityGML building records and extracts building height and storey information from the PLATEAU dataset.
| Attribute | Description | Source |
|---|---|---|
bldg:measuredHeight |
Measured building height in metres | CityGML building record |
bldg:storeysAboveGround |
Number of above-ground storeys | CityGML building record |
| Building footprint | 2D ground surface polygon | CityGML gml:posList geometry
|
Building footprints are extracted from CityGML gml:posList geometries and transformed from the source Japanese CRS into WGS84 coordinates suitable for OSM/PostGIS workflows.
Coordinate transformation: EPSG:6697 → EPSG:4326
The workflow converts PLATEAU polygons into standard WKT geometry for downstream spatial comparison and conflation.
Things Worth Knowing
- The process currently supports LOD0 (2D footprint) and LOD1 (simple block model) levels of detail.
- PLATEAU also contains roof types, roof geometry, and advanced LOD2/LOD3 semantics, but the current process only extracts height, storeys, and footprint. No roof tagging is applied at this stage.
- PLATEAU datasets cover a wide range of semantic layers (roads, land use, bridges, vegetation, disaster layers, terrain, urban facilities), but the current process only handles
bldg:Building.
Tagging
| OSM Key | Value | Notes |
|---|---|---|
height=* |
bldg:measuredHeight |
Height in metres |
building:levels=* |
bldg:storeysAboveGround |
Above-ground storey count |
source:height=* |
PLATEAU |
Source attribution tag |
source:levels=* |
PLATEAU |
Source attribution tag |
We would love the community's input on the source tags. If you have a preference or a recommendation, please share it on the community discussion thread.
Conflation and Acceptance
Unlike the Netherlands 3D BAG import, which matches buildings using deterministic ref:bag identifiers, PLATEAU data does not share a common unique identifier with OSM buildings in Japan. This process therefore uses conservative geometric conflation. Buildings are matched spatially against existing OSM building footprints using:
- Polygon intersection
- Overlap percentage
- Area ratio comparison
- Geometry validity checks
A building is skipped if any of the following apply:
- It already has a
height=*tag - The overlap between the PLATEAU footprint and the OSM building is below 70%
- The PLATEAU building footprint is significantly larger than the OSM building (area ratio > 1.2)
- The computed height is below 2.5 m
- The PLATEAU geometry is invalid (self-intersections, malformed rings, corrupted polygons)
- The PLATEAU building has no usable footprint or has ambiguous multipolygon footprints
- The PLATEAU building has a negative height value
- The PLATEAU building has no corresponding OSM building (no new buildings are created)
This conservative approach minimises risk and avoids conflicts with local mapping practices, particularly in dense urban areas where partial overlaps, adjacent buildings, and footprint drift are common.
Conflation Statistics — Osaka City
The following statistics summarise the conflation results for Osaka City (大阪市). The overlap acceptance threshold is set at a minimum of 70%, and the maximum source-to-OSM area ratio is capped at 1.2.
| Metric | Count |
|---|---|
| Total buildings in PLATEAU dataset | 616,119 |
| High-confidence matches (importable) | 181,209 |
Exclusion Breakdown
Buildings were excluded from the import for one or more of the following reasons:
| Exclusion Reason | Count |
|---|---|
| Overlap below threshold | 326,310 |
Existing height=* or building:levels=* tag in OSM |
211,936 |
| Source-to-OSM area ratio out of range | 211,713 |
| Invalid source height value | 37,567 |
| Excluded building type | 7,327 |
| Building with 3D modelling tags | 2,217 |
| Invalid source geometry | 569 |
| Total exclusion events | 611,530 |
The excluded buildings data file has been made available for community inspection on Discord. Note that the same building may appear in multiple exclusion categories, so duplicates across the files are possible.
Editing Account
Edits are performed using a dedicated account: TTmechanicalupdates, created to perform TomTom's automated edits. This ensures transparency, easy identification in object history, and separation from personal mapping.
Changeset comment example:
Import building heights from Project PLATEAU (MLIT) — Osaka city pilot #tomtom-osm #plateau-heights
Revert Plan
If a problem is identified in any batch:
- Per-changeset revert is the default mitigation, using standard OSM revert tools.
- Larger reverts (multi-changeset) are coordinated with the Japanese community via the discussion thread before action.
- The TTmechanicalupdates account is dedicated to these edits, so reverts can be scoped cleanly without affecting unrelated mapping.
Current Status
Phase: Phased rollout in progress — Osaka City (大阪市).
| Step | Status | Date |
|---|---|---|
| Publish OSM Wiki documentation for community review |  |
14 May 2026 |
| Notify Japanese community via Talk-ja ML and OSM Japan Discord | |
14 May 2026 |
| Controlled test edit (Test 1) — 14 buildings in Osaka City | |
20 May 2026 |
| Notify community on Test 1 via Talk-ja and OSM Japan Discord | |
20 May 2026 |
| Controlled test edit (Test 2) — 20 buildings in Osaka City | |
20 May 2026 |
| Notify community on Test 2 via Talk-ja and OSM Japan Discord | |
20 May 2026 |
| Share conflation statistics and excluded buildings data with community | |
June 2026 |
| Community agreement to proceed with height-only enrichment | |
June 2026 |
| Phase 1 import — Konohana, Minato, Taisho, Nishiyodogawa, Suminoe, Sumiyoshi (36,244 buildings) | |
16 June 2026 |
| Quality control checks on Phase 1 — no issues found | |
16 June 2026 |
| Share Phase 1 changesets for community review | Doing | — |
| Phase 2 import — remaining wards | Planned | Pending community review of Phase 1 |
| Create MapRoulette challenge for excluded buildings (community co-validation) | Planned | After Phase 1 review |
| Re-run conflation after community footprint improvements | Planned | TBD |
| Extend to additional Japanese cities covered by PLATEAU | Planned | In consultation with the Japanese OSM community |
Test Scope
Test 1 - Imported buildings
On 20 May 2026 we performed the first test edit of this project in Osaka City (Konohana-ku coastal area). The 14 buildings listed below have been enriched with height=* sourced from Project PLATEAU. A source:height=MLIT_PLATEAU tag has been added to each building for provenance. No existing tag was overwritten, no geometry was modified, and no new building was created.
- Changeset: 182920833
- OSMCha review: osmcha.org/changesets/182920833
- Source: MLIT PLATEAU (multi-licensed under CC BY 4.0 / ODbL / ODC-BY)
- Editor: osm-bulk-upload/upload.py v.2
- Account: TTmechanicalupdates
Map of the area
List of imported buildings
The osm_id=* column links to the live OSM object. Click any row to verify the height tag on that building.
| # | osm_id | height (m) | source:height |
|---|---|---|---|
| 1 | 576490613 | 12.6 | MLIT_PLATEAU |
| 2 | 576490639 | 6.8 | MLIT_PLATEAU |
| 3 | 576490640 | 22.9 | MLIT_PLATEAU |
| 4 | 576490643 | 9.9 | MLIT_PLATEAU |
| 5 | 632677801 | 3.9 | MLIT_PLATEAU |
| 6 | 632677831 | 11.1 | MLIT_PLATEAU |
| 7 | 632677832 | 10.5 | MLIT_PLATEAU |
| 8 | 632677848 | 4.4 | MLIT_PLATEAU |
| 9 | 632677849 | 7.9 | MLIT_PLATEAU |
| 10 | 632677850 | 3.0 | MLIT_PLATEAU |
| 11 | 632677855 | 12.9 | MLIT_PLATEAU |
| 12 | 858719092 | 9.7 | MLIT_PLATEAU |
| 13 | 858719093 | 9.0 | MLIT_PLATEAU |
| 14 | 858719094 | 8.8 | MLIT_PLATEAU |
Summary
- 14 buildings tagged in total
- Height range: 3.0 m to 22.9 m
- Average height: 9.5 m
- The area is an industrial / port zone in Konohana-ku, consistent with the height range observed (low-rise warehouses and a few taller structures)
Test 2 - 20-building scope imported
The 20-building scope announced earlier was imported on 20 May 2026 across four changesets. Same rules as Test 1 apply: height=* added only where missing, source:height=MLIT_PLATEAU on each modified building, no existing tags overwritten, no geometry changes, no new buildings created.
- Account: TTmechanicalupdates
- Source: MLIT PLATEAU (multi-licensed under CC BY 4.0 / ODbL / ODC-BY)
- Editor: osm-bulk-upload/upload.py v.2
Imported buildings
Sortable table. Click any osm_id=* to verify the height tag on that building in OSM, or any changeset number to review the changeset.
| # | changeset | osm_id | height (m) | source:height |
|---|---|---|---|---|
| 1 | 182980920 | 465404602 | 5.6 | MLIT_PLATEAU |
| 2 | 182980920 | 465404607 | 3.4 | MLIT_PLATEAU |
| 3 | 182980920 | 465404610 | 48.4 | MLIT_PLATEAU |
| 4 | 182980920 | 465404614 | 42.1 | MLIT_PLATEAU |
| 5 | 182980920 | 465404618 | 45.8 | MLIT_PLATEAU |
| 6 | 182980922 | 258414267 | 22.5 | MLIT_PLATEAU |
| 7 | 182980922 | 258414292 | 24.1 | MLIT_PLATEAU |
| 8 | 182980922 | 303037220 | 10.3 | MLIT_PLATEAU |
| 9 | 182980922 | 303157594 | 49.7 | MLIT_PLATEAU |
| 10 | 182980922 | 990873340 | 8.9 | MLIT_PLATEAU |
| 11 | 182980925 | 303157716 | 6.6 | MLIT_PLATEAU |
| 12 | 182980925 | 1487168788 | 34.1 | MLIT_PLATEAU |
| 13 | 182980925 | 1487168794 | 9.8 | MLIT_PLATEAU |
| 14 | 182980925 | 1487168795 | 10.4 | MLIT_PLATEAU |
| 15 | 182980925 | 1487168799 | 10.1 | MLIT_PLATEAU |
| 16 | 182980928 | 394719344 | 17.8 | MLIT_PLATEAU |
| 17 | 182980928 | 1487168796 | 9.8 | MLIT_PLATEAU |
| 18 | 182980928 | 1487168797 | 9.7 | MLIT_PLATEAU |
| 19 | 182980928 | 1487168798 | 9.6 | MLIT_PLATEAU |
| 20 | 182980928 | 1487168800 | 10.6 | MLIT_PLATEAU |
Summary
- Total buildings tagged: 20
- Height range: 3.4 m to 49.7 m
- Changesets: 4 (5 buildings each)
OSMCha review links
- OSMCha for changeset 182980920
- OSMCha for changeset 182980922
- OSMCha for changeset 182980925
- OSMCha for changeset 182980928
Phased Rollout — Osaka City
The Osaka City import is being executed in phases by ward groupings. The scope covers Osaka City (大阪市), not Osaka Prefecture (大阪府).
| Phase | Wards | Buildings | Status |
|---|---|---|---|
| Pilot | Test area (Konohana-ku coastal + selected buildings) | 34 | — 20 May 2026
|
| Phase 1 | Konohana (此花区), Minato (港区), Taisho (大正区), Nishiyodogawa (西淀川区), Suminoe (住之江区), Sumiyoshi (住吉区) | 36,244 | — 16 June 2026
|
| Phase 2 | Remaining wards | TBD | Planned — Pending community review of Phase 1 |
Next steps after full Osaka City completion:
- Create MapRoulette challenge for buildings excluded by the automated process, enabling community co-validation and footprint improvement.
- Re-run the conflation script to capture newly qualifying buildings after community improvements.
- Extend to additional Japanese cities covered by PLATEAU, in consultation with the Japanese OSM community.
Contact
- Project lead: [Baidoun] Salim Baidoun (TomTom)
- Japan data evaluation and sourcing: Ash Nagao & Salim Baidoun(TomTom)
- Community consultation: Can Ünen (TomTom)
Feedback, questions, and concerns are welcome via the Talk-ja mailing list and OSM Japan Discord.