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Are node ids unique in the planet osm data? If not, are they unique for a geography such as country? When a node is added to a way, does that change the osm_id of the remaining nodes? |
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Node IDs are indeed unique. Note however that node IDs, way IDs and relation IDs are separate spaces, so node 537, way 537 and relation 537 can co-exist. |
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Answering your second question, no, object IDs aren't dynamic. An existing object (be it a node, way or relation) will keep the same ID unless it gets deleted and recreated as a new object. Object IDs aren't necessarily static, though. Like I said above, someone could delete an OSM object and create a new object representing the same real-world item, which would now have a different ID. If you're wondering if you can use the OSM ID to refer to a POI, the answer is that this may work in the short term, but it isn't guaranteed to always work because someone could change the data at any point. |
