[Tagging] Source tag - deprecated for use on objects?

[Tobias Knerr]

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