Re: Strassen als Fläche

Tordanik wrote:

It is true that copying some tags to the areas would help with some less complex use cases. However, this is not a panacea, as some information cannot be simply copied (in particular, anything way direction dependent). So we have to take care to make sure that ways and areas can be matched.

Hi Tordanik,

Yes, I actually fully concur with your observations. In fact, to enable the proper rendering of the traffic junction with flyovers in Szczecin example, I did just that: I made sure ways and areas matched by fixing "over-" or "undershoots" (not exactly the right term here), and connecting up through common nodes, and fixing layer tagging as well. One extra thing I encountered, and that extents upon what is already documented: it would be desirable to also closely match up man_made=bridge features with area:highway=x and highway=x features, as otherwise the layered rendering of bridges may interfere with the display of area:highway or highway features (or the other way around depending on how you look at it...).

That said, my main concern was and is that it is probably difficult or impractical, even in a perfect situation, to fully automatically derive area attributes from ways based on common nodes or overlapping geometry topology.

Adding surface=x, as you also point out as being a "less complex use case", solves the main dilemma's. Actually, I think with surface, we have the main tag useful for area rendering anyway. There is not much sense in adding attributes like speed, access restrictions directly to an area, since the most common and accepted visualizations for these type of attributes is line. This is different for surface=x, as traditionally large scale maps, e.g. in the form of GIS or CAD files, typically list and show surface as the main attribute of areas of roads.

Tordanik wrote:

The proposal does currently enable this, so this is not meant as a criticism. I simply wanted to point out that these operations are not "unrealistic", but actually necessary – at least for some use cases, including accurate lane rendering.

As argued above, I agree it would be desirable to properly follow the tagging guide lines as described at the area:highway pages, especially the "Mapping guidelines":

http://wiki.openstreetmap.org/wiki/Prop … guidelines
http://wiki.openstreetmap.org/wiki/Prop … treet_area
http://wiki.openstreetmap.org/wiki/Prop … ea:highway