[Rebuild] Switching a tile server over to clean data

[Frederik Ramm]

Hi,

On 04/17/2012 08:22 AM, Paul Norman wrote:
> I'm also assuming that the attribution of CC by-sa tiles with CC by-sa data
> and CC by-sa tiles with ODbL data will differ.

Yes although I could see some leniency in the period immediately after 
the changeover, i.e. I think OSMF should say "for a few months after the 
changeover, even if it is technically an attribution requirement 
violation if you just leave the old "Tiles CC-By-SA Data(c) OSM" in 
place, we'll not prosecute you for that".

> If they were to render tiles from this database you would be mixing CC by-sa
> only data (the coastlines) with ODbL only data (the new planet file). As
> these are incompatible licenses, they could not do this.

No, that is not correct. Since the two databases (shapefile with 
CC-BY-SA coastline, postgresql database with ODbL content) are at no 
point mixed into a common derived database, you can make produced works 
and distribute them.

The proper attribution would have to explain that the tiles are CC-BY-SA 
and contain CC-BY-SA OSM content as well as ODbL OSM content, but there 
is nothing impossible about creating tiles that have ODbL as well as 
CC-BY-SA (or even non-open data sources).

> The next problem is the cached tiles. They will now have a mix of cc by-sa
> tiles with cc by-sa data and cc by-sa tiles with odbl data. Each tile is its
> own work, so that's not a problem, but how are you going to add attribution
> to a map where it differs for each tile?

After you have updated your coastline to ODbL, you will even have three 
different sorts of tiles: Those that are created fully from ODbL, those 
that are fully from CC-BY-SA, and those that have ODbL data but CC-BY-SA 
coastline. All three would be CC-BY-SA (although the first wouldn't have 
to be), but all three have different attribution requirements.

I think we should be pragmatic here along the lines of what I said in 
the first paragraph.

> What I see as the most practical solution is to release the first new planet
> as dual-licensed and release the next one as ODbL only. This would give data
> consumers a week to import the new planet, render some new tiles and delete
> old tiles, then change their attribution.

This is an option but maybe it confuses people more than need be? So I 
get this new planet and import it into my database and create tiles from 
it that are (at first) CC-BY-SA under dual-licensing but then at some 
future point in time I flip a switch and say "from now on, all tiles are 
CC-BY-SA under ODbL produced works clause so the attribution needs to 
change, even for those tiles that are still the same as yesterday"?

> I realize that this extends the process by a week but when you're dealing
> with as much data as OSM has there needs to be a transition period for
> consumers of the data.

It wouldn't really extend the process by a week because if someone is 
keen on using data under ODbL they could do so immediately.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"