[OSM-dev] Layered Tiling (Mapnik)

[Igor Brejc]

You're right, that would be a problem. But I guess as long as you have
raster-only data, there isn't a perfect way to solve this problem.

An alternative would be to render text (and icons, since they can collide,
too) on the client-side using JavaScript on top of server-generated tiles.
The server could still perform the actual text placement and then send the
text, text vectors and classes (=priorities) to the client which would then
render it.

Client would be able to determine that the bus stop label can be rendered if
the railway station class is turned off, for example. In advanced scenario
the client would even be able to do additional text placement automation, if
necessary.

Igor

On Tue, Dec 28, 2010 at 11:10 AM, <marqqs at gmx.eu> wrote:

> Sounds great, but it's not that easy, I think...
>
> Depending of the map layers you compose, you would need different text
> layer compositions. For example:
>
> In my public transport map, there are priorities for the texts; the name of
> a railway station has always a higher priority than the name of a bus stop.
> Hence, if there is bus stop nearby a railway station, the name of the bus
> stop is not displayed.
> Now, if you would decide to have different layers for railways and buses,
> and to switch off the railway layer, the name of the bus stop would have to
> reappear.
>
> To go one step further:
> Ideal would it be to move the colliding texts slightly instead of omitting
> them. But then, how to deal with different map layers?
>
> Markus
>
>
> -------- Original-Nachricht --------
> > Datum: Tue, 28 Dec 2010 07:30:51 +0100
> > Von: Igor Brejc <igor.brejc at gmail.com>
> > An: marqqs at gmx.eu
> > CC: Frederik Ramm <frederik at remote.org>, dev at openstreetmap.org
> > Betreff: Re: [OSM-dev] Layered Tiling (Mapnik)
>
> > On Mon, Dec 27, 2010 at 11:29 PM, <marqqs at gmx.eu> wrote:
> >
> > >
> > > But there is one problem you would have to deal with: there is no
> > collision
> > > avoidance between the texts of different tile layers.
> > >
> > >
> > That could be solved if the all the layers were rendered as a single map,
> > but painted onto several layer bitmaps. I'm planning to implement
> > something
> > like this in Maperitive.
> >
> > Igor
>
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