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Does the Overpass API provide a way to query a list of nodes and some attributes of their parent ways, and return the data in CSV format?
For example, the following will give me all motorway junctions:
[out:csv(ref, name, ::lat, ::lon)];
// gather results
(
// query part for: “highway=milestone”
node["highway"="motorway_junction"]({{bbox}});
);
// print results
out body;
>;
out skel qt;
Is there a way to query the ref=* tag of the roads of which the node is a member?
Yes, that's possible:
[out:csv(_ref, name, ::lat, ::lon)];
node["highway"="motorway_junction"]({{bbox}});
foreach { // iterate over nodes
way(bn)[highway~"^(motorway|trunk)$"][ref] -> .ways; // find ways for each node
if (ways.count(ways) > 0) { // check that at least 1 way was found
convert result // assemble result
::id = id(), // use node id
::geom = center(geom()), // and node position
_ref = ways.u(t["ref"]), // parent ref tag
:: = ::; // all remaining tags of the node
out geom; // print node
}
}
ref tags are involved: either different spellings (A8 vs. A 8), or the road name actually changes at the junction (A2 becoming S8). The solution to that probably depends on the use case: I would want two rows, one for each road, so it’s probably better to search for the roads and iterate over its junctions.
Jun 15, 2019 at 19:42
if with another foreach, and I get short of 200 results (which looks OK). Problem is, how can I refer to tags of the way from the inner foreach?
Jun 15, 2019 at 20:38