I have read Overpass API by example, but still I am unable to adapt convert statement examples to my need. What I would like to do is to get all marked routes in the area using Overpass Turbo, drop some tags and synthesize some new tags.

My query looks like this:


out body;
out skel qt;

I would like to:

  • add tag color=green when osmc:symbol contains green or when tag kct_green exists
  • add tag color=blue when osmc:symbol contains blue or when tag kct_blue exists
  • add tag kind as a value of any tags of kct_green, kct_blue, kct_red, kct_green
  • remove some tags I no longer need to reduce output file size (like kct_green)

My initial naive attempt is:


foreach (
  convert rel ::=::,
    ::id = id(),


out body;
out skel qt;

This kind of works, but lists relations without including their nodes. Moreover, I would like to perform a bit more processing on the color value:

  • I want the color to be created only osmc:symbol is present
  • I want to extract some information from osmc:symbol to color
  • I have no idea how to create the combined value from those kct_green... tags.

I guess I need something more complex, however I have found almost no documentation or examples about convert. Can someone point me in the right direction?

  • Some of the things you mentioned are only available with 0.7.55 (geometry via ::geom()) and are not yet documented (will follow soon). Otherwise, it's not quite clear what you mean by "osmc:symbol contains green". Is this meant as substring? – mmd May 14 '18 at 8:11
  • Yes, as substring. If this is not possible, how about other things? What is critical is nodes needs to be present in the output relation - without this it makes no sense to convert them. – Suma May 14 '18 at 18:59
  • Well, nodes are returned in a completely different format, as vertex: overpass-turbo.eu/s/yO2 - not sure if this helps. Also, substring processing is not possible yet as part of an expression, it's simply not implemented. – mmd May 15 '18 at 7:10
  • The trouble with using the ::geom = geom() is when I export such data as GeoJSON, they are empty. I was able to include relation ways and nodes by using > or its building blocks (way(r), node(r), node(w)), however only when not using convert. As soon as I use convert, way(r) stops working. – Suma May 17 '18 at 10:14
  • 1
    It sounds like you were better off downloading the relations, and do your own post processing locally. – mmd May 18 '18 at 8:51

After some experimentation I have found at least a way to add and remove tags:


foreach.routes (
  > -> .w;
  convert rel 
    ::id = id(),

out body;
out skel qt;

If I will be able to achieve more, I will update the answer accordingly.

  • It shows this does not work as I expected. While it outputs the relation nodes, it does not output them as a part of the relation, but next to them :( – Suma May 17 '18 at 12:17

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