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OpenStreetMaps: nodes, ways, relations and tags

Nodes, ways, relations and tags are the fundamental data structures in OpenStreetMap.
A node is a coordinate, consisting of a lattitude and a longitude.
A way is an ordered list (array) of nodes.
A relation is an ordered list of nodes, ways and even other relations. Each member in this set is assigned a role.
Then, there are also tags which are textual key value pairs to describe what nodes, ways and relations actually are in the real world.

Relation

A relation's type can be specified with the type attribute.

Using APIs to query data related to nodes, ways or relations

OSM API

The data of a way (or node or relation) can be queried with the OpenStreetMap API, for example like so: 
curl -s -X GET https://api.openstreetmap.org/api/0.6/way/1154969870

Overpass API

The data related to a given node can be queried using the Overpass API with the following query: 
node(26863664);
out;
In addition, the Overpass API provides areas as an extension to the three basic OSM data types nodes, tags and relations.

Index