Center attribute missing on OSM entities

[labiang]

The "center" attribute that sometime is received from an Overpass response is missing in the implementation of the osm4j parsers (especially XML parser).

The center attribute belongs to ways/relations and looks something like this: <center lat="46.2965728" lon="8.7908617"/>

Example of a whole tag (including center attribute):
<way id="458341945" version="2" timestamp="2021-04-26T18:48:09Z" changeset="103656292" uid="74900" user="FischersFritz"> <center lat="46.2965728" lon="8.7908617"/> <nd ref="4543689513"/> <nd ref="8669512158"/> <nd ref="8669512156"/> <nd ref="8669512155"/> <nd ref="8669512157"/> <nd ref="4543689514"/> <nd ref="8669512151"/> <nd ref="8669512149"/> <nd ref="8669512148"/> <nd ref="8669512150"/> <nd ref="4543689515"/> <nd ref="8669512146"/> <nd ref="8669512145"/> <nd ref="8669512144"/> <nd ref="8669512147"/> <nd ref="4543689516"/> <nd ref="8669512154"/> <nd ref="8669512153"/> <nd ref="8669512152"/> <nd ref="8669512159"/> <nd ref="4543689513"/> <tag k="building" v="yes"/> <tag k="castle_type" v="palace"/> <tag k="historic" v="castle"/> <tag k="name" v="Castello Marcacci"/> </way>

[sebkur]

Interesting, thanks for bringing this up. I'm not sure about a good way of handling this.

[labiang]

@sebkur I was already able to mimic such behaviour by creating derived classes of the handlers and such from the OSM4J library...
In the SAX handler, I added the parsing of the "center" tag.

I will probably fork this project, implement this functionality and then create a pull request to add it into the main repo.

I need this functionality for something that I am working on (which works closely with OSM and Overpass).

[sebkur]

my only worry is that this is a bit non-standard, i.e. the center element is not really an OSM api but something overpass-specific. If there should be more of those, it could clutter the API a bit. But not sure this is a concern we should be worried about. Does overpass also support this center element for relations? does it also support other non-standard extensions of the data types?

[sebkur]

OK, I just checked, the <center> element is also present on relations

[labiang]

Sorry for the delayed response; Yes it is present on any type of OSM element and represents the interior point coordinates of that element.