[OSM-talk] stop deleting abandoned railroads

Lester Caine lester at lsces.co.uk
Fri Aug 14 21:51:13 UTC 2015

On 14/08/15 22:03, Ian Sergeant wrote:
> On 15 August 2015 at 00:12, Lester Caine <lester at lsces.co.uk
> <mailto:lester at lsces.co.uk>> wrote:
>     As I have said before 'Delete' is something that should never happen on
>     what has at some time been correct information. 'Archive' is the correct
>     term and making that data available as required ... Delete is only
>     appropriate when the material is proven invalid.
> Your 'never delete' argument, is of a very different form to the 'never
> delete abandoned railroads' argument.  I suspect the railway=abandoned
> people wouldn't care less had the nodes been intelligently replaced by
> more accurate ones.  They are interested in the line of the railway, not
> the OSM markers that make it up.
> Your argument is to preserve some kind of history.  And OSM sort-of does
> that because nothing is ever deleted - it is all in the full database. 
> But you want everything to be in the active database instead.  But OSM
> doesn't support that - because today's lake way is tomorrow's
> multi-poly, and the next year (hopefully!) we'll have a better way to
> represent it at OSM level.  Today's one-way freeway is 17 ways
> after yesterday's survey edits get done.  I'd suggest you first work on
> an OSM model that actually supports continuity of objects, and then
> we'll do the Wikipedia linking, and then we'll talk about never deleting.
> Of course people should show respect to previous mappers.  Not tearing
> down other's work is the essence of a community project.   But also is
> the knowledge that your work isn't sacrosanct.  And OSM isn't open
> history map, and isn't a record of everything that ever was.

It is a simple fact that the current model is not suitable for many of
the functions that have already evolved. That a way varies from a single
linear element to a complex of multi-polygons depending on the
resolution is not something that the current model can handle. 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. Rather than having to
recover the data from the change log ...

Objects that have evolved but still retain an element of their former
use may have a stop date that indicates when that change occurred, and
some data consumers have the option to ignore them, but the current
'use' may be enhanced by such additional notes as on old track bed or

Lester Caine - G8HFL
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