[OSM-talk] Keep Mapnik relevant

Matthias Julius lists at julius-net.net
Wed Jan 7 20:55:26 GMT 2009

"Tomáš Tichý" <t.tichy at post.cz> writes:

>> Changing a tag from railway=abandoned to railway=dismantled just to stop
>> it rendering is one of the no-nos in OSM: tagging for the renderer.  It
>> would be much better to tag the line correctly and fix the renderer so
>> they don't render on the Mapnik map.  Then a railway map or historic map
>> could render it properly.
>> Cheers, Chris
> No, this is not tagging for renderer and I think it is perfectly
> correct. Abandoned and dismantled railway are two different things in
> reality and therefore they should be tagged differently.
> railway=abandoned is course of old railway physically present and more
> or less clearly visible in landscape. This should be rendered on
> general purpose OSM map just like buildings, highways, amenities etc.
> just because it exists and could be used for orientation and
> navigation.
> railway=dismantled is "virtual" feature saying that there were railway
> in this place one day, but it is gone now. It should not be rendered
> on general purpose map, because it no longer exists in reality. It may
> be rendered on special historic maps.

What you are describing here seems to fit well railway=disused and
railway=abandoned as described on Map Features:

A section of railway which is no longer used but where the track and
infrastructure remains in place. See disused=yes for alternative

The course of a former railway which has been abandoned and the track
and infrastucture removed. Designation not to be used if the feature
has been turned into another use, eg cycleway. 

If historic data is within the scope of OSM then it surely is not only
of interest for railways.  Therefore a generic way of tagging should
be used that can apply to any object.  Maybe removed=yes|<date>


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