A technical reference for engineers building and operating production OpenStreetMap data pipelines.
PBF/XML parsing · tag normalization · topology cleaning · routing-graph extraction · replication & diff sync · rule-driven validation · Python automation at continental scale.

Read it at www.osm-data-processing.org →

OpenStreetMap has grown from a volunteer mapping project into foundational geospatial infrastructure — the base layer under routing engines, navigation stacks, urban analytics, and machine-learning feature stores. Turning its raw, continuously-edited extracts into clean, reproducible datasets is a real engineering discipline, and this site is a deep, practical reference for that work.

Every page is written for mapping engineers, OSM contributors, GIS analysts, and Python ETL developers who need deterministic, reproducible workflows at continental scale. Expect byte-level format dives, memory-aware streaming patterns, runnable Python, and rule-driven quality assurance you can wire straight into Dask, Ray, or plain multiprocessing — not surface-level overviews.

The material is organised into four tracks, each an in-depth reference with step-by-step guides, runnable code, hand-drawn diagrams, and error/remediation tables.

• OSM Data Fundamentals & Architecture — the node/way/relation data model, PBF vs XML serialization, the binary block layout, coordinate reference systems, spatial indexing (R-tree, H3, Quadkey), tag taxonomy, and ODbL licensing.
• Parsing & Tag Normalization Workflows — choosing a parser (pyosmium vs pyrosm vs osmium-tool), async PBF ingestion, memory-efficient chunk processing, batch attribute mapping, regex value cleaning, and routing-graph conversion with OSMnx.
• OSM Replication & Diff Sync — keeping local extracts current with .osc.gz change files, replication sequence numbers and state tracking, full-history .osh.pbf processing, and building an automated minutely update pipeline.
• OSM Data Quality & Validation — authoring validation rules across JOSM, Osmose, and Python; geometry validation and repair; routing-graph topology QA; and tag/attribute consistency checking.

• Spec-grounded, not hand-wavy. Size ceilings, encoding rules, sequence semantics, and winding-order invariants are cited to the OSM Wiki and protobuf spec, so the code matches the format.
• Runnable, production-shaped code. Python 3.10+ with type hints, a consistent logging pattern, streaming-first memory discipline, and quarantine-over-abort error handling.
• Failure modes up front. Every guide names the subtle bugs — unreset delta accumulators, varint misreads, orphaned references, out-of-order diffs, self-intersecting rings — before they cost you a pipeline run.
• A tight reference graph. Concepts link to the pages that define them, so you can go as deep as a topic needs without losing the thread.

A static site generated with Eleventy, hand-authored inline SVG diagrams, KaTeX for coordinate math, and Prism for syntax highlighting — deployed on Cloudflare. The source in this repository is the complete content and templates behind www.osm-data-processing.org.

→ Start reading at www.osm-data-processing.org

More projects from the same author live under the osm-data-processing organization on GitHub.