rebuild overpass height by osm data
https://github.com/lxteo/Cities-Skylines-Mapper/blob/master/Mapper/RoadMaker.cs#L81
You can't use layer attribute of way as roads' elevation, this will make roads' slope change rapidly.
《基于 OSM 路网数据生成立体立交道路的尝试》
https://littlepotato.me/2018/05/20/build-3d-intersection-by-osm-data/