This is all OSM-based. OSM is one big pile of data - we don't do layers. It is also best to add it directly into OSM, importing data afterwards is tricky. My

This is all OSM-based. OSM is one big pile of data - we don't do layers. It is also best to add it directly into OSM, importing data afterwards is tricky. My talk at Why25 should be a good intro (https://media.ccc.de/v/why2025-198-openstreetmap-for-beginners https://media.ccc.de/v/why2025-198-openstreetmap-for-beginne...), but the OSM-wiki also contains some valuable sources: https://wiki.openstreetmap.org/wiki/Tags https://wiki.openstreetmap.org/wiki/Tags , https://wiki.openstreetmap.org/wiki/Map_features https://wiki.openstreetmap.org/wiki/Map_features There are also various libraries to show OSM as background map on a website and allow you to draw features on top. Those support various formats (GPX, GeoJSON, ...) Leaflet and MapLibre are the biggest here, with leaflet being the easiest and MapLibre being very flexible and performant