Open data. Visible limitations.

OpenStreetMap

Facility records originate from OpenStreetMap contributors and are licensed under the Open Database Licence (ODbL). Each record retains OSM type, ID, retrieval time and source modification time when supplied. Attribution remains visible in the application and map.

Overpass API

A controlled import retrieves supported facility tags through Overpass. Records are normalised and cached in PostgreSQL, rather than requested during map movement. The default study area is the Pulau Pinang level-4 administrative area. Optional bounding-box imports may include neighbouring states.

Coordinates and map services

Storage and GeoJSON interchange use WGS84 / EPSG:4326. Geography operations measure in metres. The configurable default basemap is CARTO Positron, with provider and OSM attribution displayed by MapLibre.The public edition searches facility names, towns and addresses in the Penang snapshot. It makes no external geocoding requests. Select a map point for other locations.

DOSM administrative boundaries

State and district polygons come from the DOSM data-open snapshot, with its Open Data License and revision retained. The pilot excludes records outside the state polygon while preserving the original inventory. Published polygons are an analysis reference, not a cadastral determination. The invalid Timur Laut source geometry was explicitly repaired with PostGIS; repair provenance and original files are retained. DOSM source snapshot.

Retrieval status

The dashboard shows the actual latest database import. There are no preloaded invented facilities. The public edition serves a published snapshot; new data requires a fresh export and publication.

Data limitations

OSM is a community dataset and may contain omissions, stale facilities, duplicates representing distinct OSM objects, or missing names and addresses. Facility tags alone do not confirm public ownership or unrestricted access. Refresh upserts observed records but does not remove deleted OSM objects; periodic reconciliation is planned.