On 02.01.2013 14:16, Chris Hill wrote: > Secondly, any changeset can have multiple sources so adding the source > tag to a changeset is not flexible enough.
Any object can have multiple sources, so adding the source tag to an object is not flexible enough either. There are workarounds for either limitation - such as multiple source tags per object, or multiple small changesets. In practice, few care. > Source tags are useful, sometimes on changesets, sometimes on objects, > but if you do change an object using a new source, please reflect that > by changing the source tag. The history of the object will show where > that changed if anyone is interested. And that's a fundamental problem with per-object source tags: It forces additional work on mappers changing the object in the future. Let's improve a few buildings using Bing imagery: - This building has source=landsat, need to replace with Bing. - This other building has source=Yahoo, need to replace with Bing. - This other building has source=Yahoo;survey, need to replace with Bing;survey. But only assuming that "survey" refers to the unchanged house number, which I don't know for certain, so let's bring up the object history anyway ... And so on. This drawback is not even apparent to the first mapper, the one creating the object - and thus the source tags on objects are used quite liberally. But I still think it's not a good idea (maybe except in cases where unexpected sources are used). Tobias _______________________________________________ Tagging mailing list [email protected] http://lists.openstreetmap.org/listinfo/tagging
