The goal is to construct a data structure that takes the id of a node/way/relation and returns the pair of lat/lon or the collection of lat/lon coordinates assigned to it. So far, I have downloaded the osm file of my city, gotten rid of superfluous nodes like those pointing to amenities, and then used osmconvert with the all-to-nodes feature to construct a csv file that contains the columns @Id@name@lat@lon. This approach does work to construct a look up system for id(of node)->lat/lon. But not for id(of relation/way)--> List of lat/lons. Does anybody know if there is a osmconvert feature or another way to retrieve this kind of list or csv file.