[OSM-talk] stop deleting abandoned railroads

moltonel 3x Combo moltonel at gmail.com
Thu Aug 20 13:06:11 UTC 2015

On 19/08/2015, Lester Caine <lester at lsces.co.uk> wrote:
> 98% of the history that we are looking to manage properly is currently
> existing in OSM. All that is needed is to add start dates to the bulk of
> the existing data.

What do you do when a road gets upgraded, widened, straightened,
renamed, or some combination thereof at various points in time ?
start/end_date tags are way too crude, they can't capture any
evolution (as opposed to construction/demolition) of the real world,
making their use very limited.

> The SMALL amount of material that
> is a result of new development work invariably maps into currently
> existing objects.

That's just not true, by definition new developments are new objects
(and often a lot of old objects relegated to the past). And the amount
of evolution in the real world is by no mean small.

> Insisting that this data is only available for
> rendering purposes in a second database is just wrong, and even worse,
> the 98% of the supporting data exists in OSM so why maintain a second
> copy of it.

I would actually love to be able to map the past in OSM. But if all
you have to offer me is start/end tags and some renderer/editor
workarounds, I'll say no thanks.

To me OHM's value is not so much in its data as in being a sandbox to
experiment with tooling to map the past, which can eventually be
merged back into OSM. I suppose the OSM data model itself has to be
modified to support a nonlinear history, but this is tricky.

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