[mkgmap-dev] Commit: r1445: Hide underground railways. Map railway=abandoned to highway=track.

Tue Dec 29 10:59:21 GMT 2009

Quoting Marko Mäkelä <marko.makela at iki.fi>:

> Hi Charlie,
>
> On Tue, Dec 29, 2009 at 09:56:12AM +0000, charlie at cferrero.net wrote:
>> Quoting svn commit <svn at mkgmap.org.uk>:
>>
>> >
>> > Version 1445 was commited by marko on 2009-12-29 09:45:48 +0000
>> > (Tue, 29 Dec 2009)
>> >
>> > Hide underground railways. Map railway=abandoned to highway=track.
>>
>> Out of curiosity, why hide underground railways but not underground roads?
>
> Because, as far as I know, Garmin units do not support railway navigation.
> Actually, the underground railways are now omitted from the translation
> altogether; I do not know how to create invisible routeable ways.
>
> The reason why I committed this change is that underground railway tracks
> tend to be very long and built deep underground, below roads or even
> residential areas.  There is a 30km long harbour tunnel near my home
> (not completely mapped yet, but I already find it a little confusing to see
> it on the map).  Also, some time ago, I found it confusing to see subway
> tracks running through a pedestrian area in the centre of Helsinki.
>
> Given that Garmin units do not work deep underground, omitting the   
> underground
> railways should not hurt navigation.  Railways that are visible on the ground
> can be useful, especially when visiting incompletely mapped areas.
>
> I may create map layers for public transportation routes in the near future.
> Then I will have to make sure that underground railways do appear on the
> railway route layer.
>
> If someone knows how to create invisible routeable ways, then we might
> consider hiding underground roads.  I would only do that when a special
> tag is set, for very long tunnels that go through cities, such as those
> in Stockholm, Sweden or Brussels, Belgium.
>
> Best regards,
>
> 	Marko
It would be good to create invisible routeable ways for places like this:
http://www.openstreetmap.org/?lat=51.512189&lon=-0.117448&zoom=18&layers=B000FTF

Whilst mapnik renders the Strand Underpass fine, mkgmap creates a  
nasty looking road going straight through the various buildings.   
Unfortunately I think that GPS units plot polygons first, then lines,  
so there's no single-layer solution at the moment.

A multi-layer solution is to have:
Visible layer, which does not plot highway=* & tunnel=yes
Routing layer, which does.

This way you don't see the tunnel roads on the map, but you can route  
through them.

-- 
Charlie