Overpass API: Get coordinates of postal boundary

Question

How can I use the overpass-API to recursively get all nodes and their coordinates which belong to the ways of an relation? I need this to draw bounding polygons of all the postal areas inside a city.

I have the following query:

<osm-script>
<area-query ref="3600062649" />
  <recurse type="up" />
  <query type="relation">
     <item />
     <has-kv k="boundary" v="postal_code" />
  </query>
<print />
</osm-script>

This returns all relations with postal boundary inside the queried area and all the ways of these relations, however it does not return the nodes/coordinates of the points which make up these ways:

<relation id="1300371">
   <member type="way" ref="51702433" role="outer"/>
   ...
   <tag k="note" v="04451 Borsdorf"/>
   ...
</relation>
<relation>
....
</relation>

I would like to get a list of postal areas with their nodes, like this:

<relation id="1300371">
   <member type="way" ref="51702433" role="outer">
      <node id="323735839" lat="51.3751873" lon="12.5689796" />
      .... 
   </member>
   <tag k="postal_code" v="04451"/>
   ...
</relation>

The tag with the postal code should still be included so I can distinguish all received postal areas.

Answer 1

I would recommend the following approach: it returns coordinates for ways' nodes 'in place', like you described in your question.

The only thing, which is missing in the output is the technical OSM node-id (ref). I assume that for use case of drawing some boundary area on a map, this is most likely not needed. If you take a look at the screenshot below, overpass turbo is drawing all postal code areas on the map without any issue.

area(3600062649);
rel(area)["boundary"="postal_code"];
out geom;

http://overpass-turbo.eu/s/7In

Example output:

  <relation id="1301656">
    <bounds minlat="51.3145882" minlon="12.2366519" maxlat="51.3391521" maxlon="12.3034696"/>
    <member type="way" ref="87537618" role="outer">
      <nd lat="51.3179538" lon="12.2426125"/>
      <nd lat="51.3178723" lon="12.2414464"/>
      <nd lat="51.3176008" lon="12.2399198"/>
    [...]
    </member>
    [...]
    <tag k="boundary" v="postal_code"/>
    <tag k="note" v="04205 Leipzig"/>
    <tag k="postal_code" v="04205"/>
    <tag k="postal_code_level" v="8"/>
    <tag k="type" v="boundary"/>
  </relation>

Answer 2

Try the following:

1. Copy your overpass-api query to clipboard
2. go to https://overpass-turbo.eu
3. paste your query in the left screen by deleting any other content before there.
4. Run your query on that service,
5. wait that an alert comes up about missing information to display nodes from OSM objects
6. agree to auto-repair your query
7. Re-run your query in overpass-turbo
8. on the left side, switch from map view to data view
9. Tell us whether that is the result you want.