[OSM-talk] Keep Mapnik relevant

Mike Harris mikh43 at googlemail.com
Sat Jan 17 10:48:42 GMT 2009


Were you the only recipient? I must have hit the wrong button - will resend

Mike Harris

-----Original Message-----
From: Ed Loach [mailto:ed at loach.me.uk] 
Sent: 15 January 2009 11:17
To: 'Mike Harris'
Subject: RE: [OSM-talk] Keep Mapnik relevant

Did you mean to Reply All, or was this just for me?

All the best


> -----Original Message-----
> From: Mike Harris [mailto:mikh43 at googlemail.com]
> Sent: 15 January 2009 10:49
> To: 'Ed Loach'
> Subject: RE: [OSM-talk] Keep Mapnik relevant
> I've been watching this thread for a while and add these
> thoughts:
> 1. The 'railway' issues: Would a simple fix be to label 'abandoned 
> railways'
> by using a relation? They are effectively now a relation of type=route 
> that may include ways that are now on the ground as e.g. a footway, a 
> bridleway, a cycleway, etc. as well as ways that no longer exist. Only 
> the last of these would need tagging - and here the tag would not, by 
> definition, conflict with any other tag as the way is no longer there. 
> This is also consistent with the general concept of mapping what is 
> there on the ground - without losing the information regarding the 
> route of an abandoned railway that might be of great interest to 
> railway buffs.
> 2. The former shop / pub etc. issues: the use of abandoned:xxx= and 
> former:xxx= tags may be helpful - but may they not sometimes rather 
> overlap?
> There is also a risk of overuse. On the other hand, even from the 
> point of view of "map what is there" there is a case, IMHO, for some 
> tagging of "what is no longer there". Examples in my area are:
> A. A large school. The OS maps (even the latest digital
> edition) show it as
> a school covering a considerable area. Aerial photography (e.g.
> Google)
> shows a demolition site. On the ground there is no trace of any 
> buildings - just a park (appropriately "Phoenix Park") criss-crossed 
> by footways and cycleways and allowing some very useful links to be 
> made between streets on either side of the area that were clearly not 
> links when they went right through the school buildings. All of this 
> has happened in a very few years, witness the OS mapping. As an OSM 
> user I would want to know that I can use these linking ways and to be 
> reassured that the OS map is wrong and more out-of-date than OSM ... 
> So a need to include the former:xxx= tag. OSM currently shows just the 
> park, no footways or cycleways and no school. I couldn't tell in 
> advance of visiting the site whether OSM had not yet added the school 
> or whether the OS map was out of date.
> B. Tennis courts and football field. The boundaries are shown on the 
> OS but not labelled. Yahoo aerial photography shows outlines but I 
> couldn't say their status. OSM tags these features as sport= and 
> disused=yes. Mapnik doesn't render them at all but osmarender shows 
> them as if they were live and available facilities (ignores the 
> disused=yes tag
> presumably) - so you
> don't know that you can't play sports there unless you go to the edit 
> page.
> On this occasion, the disused= tag adds a third option to 'abandoned' 
> and 'former'! It would be good either for the features not to be 
> rendered or for them in either renderer or for them to be rendered in 
> both renderers but distinguished as not being available for would-be 
> tennis of football players!
> We do need to work some consistency into this area ... Who decides? 
> How can the debate be structured to work towards consistency and 
> consensus?
> Mike Harris
> -----Original Message-----
> From: Ed Loach [mailto:ed at loach.me.uk]
> Sent: 13 January 2009 23:45
> To: 'Andrew Chadwick (mailing lists)'; talk at openstreetmap.org
> Subject: Re: [OSM-talk] Keep Mapnik relevant
> > And later on, if the building
> > gets
> > used for something else, you could perhaps change it to:
> >
> >    shop=candy
> >    name=Fred's Wine Gum Emporium
> >    former:amenity=pub
> >    former:name=The Blue Grape   # or old_name
> >    former=<date>      # ugh, mabye not
> >
> > Well, it appeals to the stupid, plodding, pattern-seeking
> part of my
> > brain, kinda.
> But it probably is too limited.
> A couple of examples that spring to mind. A building in Wolverhampton 
> that was a cinema when my dad was young has since been things like a 
> bank and a pound shop at various stages and I think is now a pub. How 
> many former tags will you support?
> Similarly there was a shop in Oxford that was a cheese shop (Little 
> Clarendon Street circa 1987) that was a childs toy or clothes shop (I 
> forget
> which) the following year and I am sure is something else again now.
> And the Woolworths in Wolverhampton which until recently (I'm assuming 
> it is now closed) was the "lower ground" version of the Woolworths I 
> remember as a child which was about 4 floors tall in total. I believe 
> Boots took over what used to be the Woolworths ground floor but I 
> moved away almost a decade ago so my memories are a little rusted.
> There are shops near here that probably have a different business (or 
> two) in them every year. If you're going to go with prefixes you'll 
> want something like 20080101-20080606:name=Spring Fashions Limited and 
> 20080607-20081231:name=Fireworks'R'Us (names made up).
> For now I'm mapping what is actually here. If something changes in 
> reality I change it in OSM. If at some point in the future OSM 
> supports historical mapping in some way then I may look at perhaps 
> going to the effort of adding historical tags as well as updating the 
> existing ones.
> Railways, which I
> think may have triggered this discussion (or may have cropped up 
> recently on another related email
> list) are an interesting case. Abandoned railways are something that 
> currently exist in places, until they are converted into footpaths or 
> something else. This isn't as such historic mapping as mapping the 
> bits of an abandoned railway that still exist. Disused pubs are 
> something I'm in two minds about. In some cases the building is an 
> obvious landmark which would be a useful PoI whether it opens or not. 
> And whether it opens or not is something which would be useful 
> additional information for anyone wanting to visit the place. But 
> disused pubs where the sign has been removed and it has perhaps 
> changed to residential use I don't feel should still be marked. A bit 
> like "the old post office" or "old bakehouse" as properties 
> surrounding an office I used to live were both residential properties 
> (one of which was rented on behalf of Mark McGhee when he was managing 
> Wolves, and we could see into his kitchen from our office).
> So I guess I'm in the map what exists now camp, until OSM has some 
> better method of historical (or future - and I admit I've tagged a 
> highway under
> construction) tagging.
> Ed

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