OSM Data Extract Streetnames for cities

Question

How to extract streetnames with osmosis (Java)? I have tried to process all Nodes. I put them in a Map<String, List> meaning Map<CityName, ListOfStreetnamesOfThatCity>:

@Override
public void process(EntityContainer entityContainer) {
    if (entityContainer instanceof NodeContainer) {
        final NodeContainer entityContainer1 = (NodeContainer) entityContainer;
        if(containsTagWithKeys(entityContainer1.getEntity().getTags(), "addr:city", "addr:street")) {
            final Map<String, String> tags = entityContainer1.getEntity().getTags()
                                                  .stream()
                                                  .collect(Collectors.toMap(Tag::getKey, Tag::getValue));
            if( cityStreetnames.get(tags.get("addr:city")) == null) {
                    cityStreetnames.put(tags.get("addr:city"), new ArrayList<>());
            }
            String streetname = tags.get("addr:street");
            cityStreetnames.get(tags.get("addr:city")).add(streetname);

        }
    }
}

This gives me a subset of all streets per city only. (Not sufficient)

I tried to process all Way nodes

if (entityContainer instanceof WayContainer) {
    Way myWay = ((WayContainer) entityContainer).getEntity();

    final Map<String, String> tags = myWay.getTags()
                                             .stream()
                                             .collect(Collectors.toMap(Tag::getKey, Tag::getValue));
    if(containsTagWithKeys(myWay.getTags(), "name", "highway") && tags.get("name").length() > 2) {
        names.add(tags.get("name"));
    }
}

This gives me a lot of streets but I don't know in which city these ways are located.

I'm really new to OSM data. Is there a way to map a way node to a city? Is there a better way to get all streetnames of a city?

I have used .osm.pbf for Germany from geofabrik.de.

Answer 1

Address tags are not only present at nodes, they do exist on ways and relations, too. So you need to process all elements in order to get all addr:street and addr:city combinations.

In the end this is really a task for a gecoder such as Nominatim. Your approach will work for many situations but not for all of them. For example some elements will only contain an addr:street tag but no addr:city tag. A geocoder will be able to resolve the missing city by looking at administrative boundary relations, your approach won't.