[OSM-talk] stop deleting abandoned railroads

Mateusz Konieczny matkoniecz at gmail.com
Fri Aug 14 22:14:05 UTC 2015


On Fri, 14 Aug 2015 22:51:13 +0100
Lester Caine <lester at lsces.co.uk> wrote:

> But the
> one thing that the current model has got the capability of handling is
> start and stop dates for any facet of an object from the name of a
> shop to the evolution of the road and rail system over time. That the
> 'main' database only displays elements which have not yet acquired a
> stop date is how the model currently works, while the OHM version
> simply maintains multiple time stamped versions of the same data.

This is not true. Current model - from mappers, through programs used
to edit to data consumers is unsuitable for handling several
intersecting objects, verifiable only for specialists.

> Rather than having to recover the data from the change log ...

Date of deletion is at best loosely correlated with date of
destruction of represented object. In particular most edits either are
mapping the same objects in greater detail - despite lack of change on
the ground, adding new objects present in reality since decades or in
some cases thousands of years (in case of natural forms it may be even
higher).

Many of deleted objects never represented reality.


Mapping all buildings that ever existed may seem simple for some cases.
But many cities were destroyed (partially or fully) and later rebuild.

I would delete any encountered OSM elements that are marking objects
that are fully and completely gone (obviously, I would do it only for
places where I can verify this and after asking original mapper for
clarification whatever there are some mappable traces - maybe just
tagging was wrong). One exception would be for elements representing
recently destroyed objects that were mapped to protect from recreation
based on outdated aerial images (in that case I would convert it to
ways marked with note=* asking to avoid recreation without survey).



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