Where is an intro to how data is organized in OSM?

Where might I find “basics about OSM tags,” or a discussion of how map data is organized in OSM?

For two examples,
(1) generally a feature has both geometrical info (lat/long) and also semantic info (tags);
(2) Also in OSM one cannot (or at least usually does not) describe a feature with two tags that have the same key,
e.g. one should not tag a feature with both highway=primary and highway=motorway_link

I imagine someone has written these down somewhere. But where?

Sorry if this question is a bit ambiguous… I realize explanations may not all be in one place.



I hope someone with a lot more knowledge then me gives you some information.

I find a lot of information looking through this forum and also looking at the map to see how others have tagged things.

The best information I have found on tags is the Wiki page on map features.

You can also have a look at this site it helped me when I first started


Perhaps the information “for developers” is what you are looking for http://wiki.openstreetmap.org/wiki/Develop , especially http://wiki.openstreetmap.org/wiki/Data_Primitives and http://wiki.openstreetmap.org/wiki/OSM_XML