[Talk-GB] Deletions and newbie editors

Lester Caine lester at lsces.co.uk
Mon Oct 6 09:25:47 UTC 2014

On 06/10/14 09:26, David Woolley wrote:
> On 05/10/14 22:28, Lester Caine wrote:
>> All achievable if the API monitors the constraints
>> on relations and checks that what JOSM submits is complete.
> That would represent a radical change in design philosophy.  At the
> moment, the code behind the API ("I" standards interface) implements
> very few business rules.  All it really knows about relations is that
> all the members must be currently live objects.  It implements the
> business rules by refusing changes outright.
> The big advantage of that approach is that it allows decentralised
> addition of new features.  Anyone can add a new tag, tag value, or
> relation type and create clients and, possibly, renderers that use them,
> without needing a central authority to write code to support them.
> Currently, it is the editors that implement business rules.  Whilst you
> could have common libraries, JOSM would need a Java one, but other
> clients would need ones for other languages or platforms.

The decentralised approach only works if ALL the edit tools are able to
ensure data integrity. We are now adding a layer of material that can
only be created by relations, and if someone is going to have to
manually check every one when any changes are added to the general area
it can only get worse. Coastline is probably a good example of the
problems maintaining continuous relations? That Antje has spent a lot of
time creating data which is now being destroyed is the problem and I'd
rather see some edits blocked instead of breaking the integrity of other
data. I don't see that a test for a constraint ensuring continuity is a
block to decentralisation, if only to flag that something does need fixing!

This is not a 'radical change' but rather that we now need tools that
can handle this secondary layer of material. This may need more tools
like the coastline tests but the underlying 'rules' still need to be

Lester Caine - G8HFL
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