Which purposes serves the Overpass API in the ecosystem of OpenStreetMap? What kind of OpenStreetMap data exists? What are requests?
OpenStreetMap and the Overpass API
How does the ecosystem of OpenStreetMap work?
Which role does the Overpass API play there?
The Data Model of OpenStreetMap
To understand how Overpass API works
the data model of OpenStreetMap is introduced here ahead of everything else.
Glossary
For OpenStreetMap as well as for the Overpass API, a couple of notions are explained.
Run time model
By which rules Overpass API executes a request?
Presenting each building block creates the insight
how these building boxes together are effective as a request.
Assertions
The Overpass API will specific tagging schemes neither promote nor hamper.
It is intended to be backwards compatible for decades.
Commons
The public instances await your queries.
They offer as much resources as possible,
but they also defend themselves against overuse.
Heavy users easily can set up their own instance.