[OSM-dev] Relation - Multipolygon = "Area"

[Igor Brejc]

On Tue, Apr 19, 2011 at 3:15 PM, Jukka Rahkonen <
jukka.rahkonen at latuviitta.fi> wrote:

>
> I would say that it is still rendered as an area but the fill is
> transparent and only outline coloured. Which brings to my mind another
> smallish problem with big real world area features which has been splitted
> to smaller areas so that they can be handled in OSM. If you want to render
> them with fill and outline the split lines come visible on the map.
>
>
For high quality rendering, the rendered would have to join such areas
together before drawing the outline. A typical example are
waterway=riverbanks - if you want to render blue riverbank outlines, you
need to join the areas together.

This is up to the rendering software. The problem with existing renderers
(including Maperitive, which I'm working on) is that mostly treat OSM
primitives (nodes, ways, relations) as direct graphic elements, so you get
various unwanted rendering artifacts. I'm more and more convinced something
better is needed: OSM primitives represent parts of the higher-level
features and should be treated as such. Examples:

   - A collection of road ways represent a road graph/network. Graph
   vertices are not necessarily the same as starting/ending way nodes (BTW
   Maperitive already works this way).
   - A collection of riverbank areas represent a single multipolygon
   element.
   - Various bus route relations represent a _single_ network of bus routes.
   A graph edge can represent one or more bus routes.
   - ...

Igor
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/dev/attachments/20110419/7d39361a/attachment.html>