[mkgmap-dev] Split barrier=* and traffic_calming=* to a separate layer?

Wed Jan 13 08:33:48 GMT 2010

Marko Mäkelä wrote:
> Some time ago, I faced some opposition against adding this to
> styles/default/points:
> 
> +traffic_calming=* [0x6614 resolution 21]
> 
> I was wondering if it would be worthwhile to split all barriers
> (fences, gates, bollards, whatever) and traffic_calming to a separate
> layer?  These objects are not usually searched for or routed to, and
> they are not relevant for navigation much of the time.
To an extent, I disagree.  If you're walking across the countryside, it 
is very useful for navigation to know where the fences, walls and hedges 
are.  Particularly if you tend, like me, not to pre-plan a route but 
just go for a walk/geocache ramble.

Traffic calming measures, obviously, aren't particularly important for 
walkers.

> 
> In other words, I would propose a new style that would translate these
> points and lines and remove the translations from the default style.

I have gone further, and removed all routing related info to a separate 
invisible layer.  This allows you to overcome the fact that there's only 
one routable roundabout type/style in the default.  But you need to use 
TYP files to do this properly.

> I would also propose to include a simple multi-layered map-making script
> in the mkgmap repository.  (Or two scripts, one for Windows cmd.exe and
> another for Bourne shell.)  Can someone please give me a hand with this?
> How would I generate a transparent style=barrier layer on top of a
> routable style=default layer?  (Note that no TYP files should be necessary
> for this.)  Can mkgmap already join the two layers into a gmapsupp.img?
Yes it can.  Though at the moment it doesn't seem to apply transparency 
properly (i.e. if the top layer is transparent, then mkgmap makes all 
other layers transparent too).  I posted about this a few weeks ago.

> As a bonus, how about creating installers for MapSource and RoadTrip?
> 
> Best regards,
> 
> 	Marko
> _______________________________________________
Overall, I think what you're suggesting would be quite a shift from the 
current mkgmap philosophy (at least in terms of output) of keeping it 
simple.  The moment you introduce multiple layers/styles in the same map 
you make it much harder to ensure that something isn't going to break 
somewhere on someone's GPS.