hotosm/fAIr-guru-td-highways

HOT OAM Segmentation Dataset

Semantic segmentation training data. Aerial imagery tiles from OpenAerialMap paired with OpenStreetMap labels, drawn from HOT Tasking Manager projects. The labelled feature is recorded in the feature_type column and in the generated statistics below.

Structure

One row per image tile.

Column	Description
image	256x256 RGB aerial chip, georeferenced
mask	Binary raster, 0 background, 255 feature. Empty when the feature is not rasterized
label_geojson	Label geometries for the tile, EPSG:4326
tile_id, tile_x, tile_y, tile_z	XYZ tile identity
bbox_west, bbox_south, bbox_east, bbox_north	Tile bounds, EPSG:4326
project_id, project_name, country, organisation	Source Tasking Manager project
imagery_url	OpenAerialMap TMS endpoint the chip came from
feature_type	OSM tag key the labels were filtered on
num_features	Label count in the tile
class_counts	JSON of tag values in the tile, e.g. {"residential": 3, "path": 1}
project_url	Tasking Manager project page, including the mapping instructions given to mappers

Ground resolution depends on zoom level and latitude. At zoom 19 a pixel covers roughly 0.25 m and a tile spans about 63 m.

Labels

Labels come from OpenStreetMap through the HOT Raw Data API, filtered on the feature_type tag key. Geometry follows the feature: polygons for areas, lines for roads and waterways. Full OSM tags are preserved per feature under the tags property. Tiles containing no labels are kept as negative samples.

Label completeness follows OpenStreetMap coverage at extraction time. Imagery and labels can be captured at different dates, so a feature visible in a chip is not guaranteed to appear in the labels.

Splits

Splits are assigned per project, keeping tiles from one project together to avoid spatial leakage. Projects sharing an imagery URL cover the same ground and are assigned as one group.

Sources and licensing

Component	Source	License
Imagery	OpenAerialMap	CC-BY 4.0, attribute contributors of Open Imagery Network
Labels	OpenStreetMap	ODbL 1.0, attribute OpenStreetMap contributors
Project metadata	HOT Tasking Manager

Provenance

Built with tm-oam-ds-builder. Per-project metadata, areas of interest, and aggregate statistics ship alongside the Parquet.

Generated Stats

• Dataset version: 0.2.1
• Tile pairs (num_examples): 323
• Total projects: 1
• Feature type: highway
• Tiles with labels: 299
• Tiles without labels: 24
• Total label features: 934
• Avg roads per tile: 2.9
• Total area: ~2.9 sq km
• Countries: 1
• Generated at: 2026-08-05T23:41:59.049564+00:00

Label classes (OSM highway tag)

Class	Features	Share
residential	681	72.9%
path	211	22.6%
service	34	3.6%
footway	8	0.9%

Coverage by Country

Country	Projects	Tiles	Roads	Area (sq km)
South Africa	1	323	934	2.9