An OSM extraction pipeline separates acquisition, geometry assembly, normalization and validation. Keep an immutable copy of the raw response so that a later schema or conversion change can be reproduced without requesting the same data again.

Record the acquisition

Save the query, endpoint, geographic boundary, timestamp and response checksum. Check for a service error or truncated response before converting it. For large regional processing, use a dated bulk extract rather than repeated overlapping API queries.

Assemble geometry and fields

Use an OSM-aware converter to reconstruct ways and relations. Preserve osm_type and osm_id together, along with original tags. A representative center returned by Overpass is not a polygon geometry.

Normalize fields into documented names and types. Keep identifiers as strings where necessary to avoid numeric precision loss. Convert units explicitly; leave missing values null or absent according to the schema. Keep source and inferred classifications distinguishable.

Deduplicate and validate

Deduplicate repeated observations by element type plus ID. Review records representing the same real-world feature through different elements rather than automatically merging them. Check geometry validity, coordinate bounds, feature counts, field types and the number of rejected records.

Deliver the GeoJSON, a field dictionary, source/query record and a short rejection or change log. Retain OSM attribution and review distribution requirements.

Attached Temane normalization

The cells below load the retained response-derived sample and show its normalization, counts and map. They operate on attached files and make no new OSM extraction request.

References and related work

Overpass query design · Merge and deduplicate · OSM copyright