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I was searching for OSM documentation online, but I couldn't find one. This is my question,

In OSM(raw data format), does the road segment has intersections included in them. If so, are the intersections are identifiable?. Also, are there any detailed information available about OSM (WiKi is not complete)?.

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  • For a better understanding of the OSM data model just fire up an OSM editor (iD or JOSM) for your local area and take a look at the raw data. – scai Jun 21 '17 at 6:36
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In the OSM raw data, all ways (roads or else) are described as a sorted set of node numbers. Roads can be identified by a highway-tag, with some exceptions like highway=bus_stop, bridleway or footway.

A road junction is just a node, the roads don't have to be split up there. Roads crossing with bridges should not have a common node.

To identify a road junction, you have to take every node of a way, and look up all other ways that are tagged as roads if they share the same node.

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  • So roads intersect only by virtue of the fact that a node belonging to one also belongs to the other - but in the data itself in effect it's the ways (roads) which know what nodes they are made up of - not the nodes that know which ways they belong to. The only (?) exception to this as a starting point is where data is recorded about turn restrictions - but then data about the relationship of one road to another is stored in a third category of feature (a relation). wiki.openstreetmap.org/wiki/Relation:restriction – Rostranimin Jun 23 '17 at 15:24
  • Relations of type destination_sign work similar: wiki.openstreetmap.org/wiki/Relation:destination_sign – AndreJ Jun 23 '17 at 15:31

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