[GIS] A way to search street intersection on openstreetmap

openstreetmapoverpass-api

I need to find intersection by searching name of 2 streets; I found overpass API to query on osm data; the way I found was to find a node near a way; but the problem is all nodes don't have name and in most cases the answer isn't accurate, is there a better way?

Best Answer

You could use the following approach:

[bbox:{{bbox}}];
way[highway][name="6th Avenue"];node(w)->.n1;
way[highway][name="West 23rd Street"];node(w)->.n2;
node.n1.n2;
out meta;

Try it on overpass turbo: http://overpass-turbo.eu/s/6Pb

Edit: node.n1.n2; calculates the intersection of input set .n1 and .n2. Please check the documentation for details.

Related Solutions

Overpass API Nodes – How to Get Nodes in Correct Order

(I edited my answer for your follow-up questions)

You have to use the order in which the node IDs are referenced by the corresponding <way> element in the XML file. In contrast, the order in which the <nodes> elements appear in the XML file is completely irrelevant.

Furthermore, as you already discovered, a relation can contain multiple separate ways forming a single polygon. Here, the relation doesn't necessarily has to reference the ways in the correct order. Consequently the correct order of the ways has to be determined by looking at the first and last node of the way. Consecutive ways will share the same last and first node.

For a neat sorting algorithm you can take a look at the source code of JOSM.

Alternatively you might take a look at overpass turbo which provides a GeoJSON output which Leaflet should be able to handle.

OpenStreetMap – Correct Order of Nodes in Overpass API Query

Nodes don't have any order themselves. Keep in mind that a single node can be part of multiple ways. Therefore each node can have a different position for each way it belongs to. Hence you have to query for the way, too, to get the order of its nodes:

way(35565161);
out body;
>;
out body;

way(35565161);
(._;>;);
out body;

See the result on overpass turbo.

The order of <node>s inside the result is completely irrelevant. The relevant information is the order of <nd>s inside the <way> your are interested in. Each <nd> element will reference a specific node ID, the order of all <nd> elements represent the order of nodes for this particular way.

Best Answer

Related Solutions

Overpass API Nodes – How to Get Nodes in Correct Order

OpenStreetMap – Correct Order of Nodes in Overpass API Query

Related Question