I have a OSM node Id/ latitude-longitude for a point in the road(say point Z). How do I find the previous x points that I need to travel to reach Z in all directions? I was thinking overpass API could help me. But it is able to return points only with tags. I am not able to get it return the node Ids on the road/way.
Can you please suggest any API/tutorial that could help?
On
I suggest to get started by reading about OSM elements, especially nodes and ways. Afterwards take a look at OSM XML format. It might also help to open an OSM editor (e.g. iD) and to take a look at the raw data.
Nodes don't have any order or "next node" themselves. Nodes can be part of one or multiple ways. Each way references a list of ordered nodes. So you have to look at all ways a node belongs to, then look at the way's node list to determine the previous and next nodes. If the node is at the start or end of a way then you have to look if there are one or more consecutive ways. Consecutive ways share the same node at their start/end.
if i'm not wrong what you are asking is: given a osm node id with coordinate x and y what are all points to do in order to arrive there from a starting point? if this is the question well this is a graph oriented question; you should create a grah and then use some algorithm in order to find all the routes between starting point and end point; you should use some graph oriented software.. something like neo4j and spatial contrib (https://github.com/neo4j-contrib/spatial) In past i built a project where i read an osmfile, create a graph and used A* algorithm; you may give to it a look https://github.com/angeloimm/neo4jAstarTest