Martin Koppenhoefer schrieb: > 2009/11/25 Tobias Knerr <o...@tobias-knerr.de> > >> Jean-Marc Liotier wrote: >>> Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) >>> stired my interest. Using a few examples, he showed how mapping >>> everything as an area - or as a volume - makes ultimate sense. Should we >>> go for it now ? >> Imo, area mapping is too advanced for now. After all, >> - it's quite hard to get the data (several width measurements required) >> > well depends on the quality you want to achieve (can do it with aerial > images just now) [...]
That's an additional requirement, though, so it's not possible everywhere. >> - there aren't many practical applications > there is one key application: rendering For most maps (or most zoom levels of most maps), it's not that useful to use real outlines for ways. A linear abstraction with exaggerated (and possibly importance-dependent) widths is common and usually more practical. >> - you can't work around some editing problems with shared nodes anymore >> > don't understand what you intend There have been several discussions whether area borders - such as landuse areas - should use the same nodes as streets they are adjacent to. Iirc, some participants complained that sharing nodes causes editing problems - making it hard to select individual ways, requiring the relatively unknown unglue operations when editing the ways etc. With streets represented as areas, the "way=middle-of-the-road" argument wouldn't apply, so we probably would have to start dealing with overlapping ways and/or shared nodes. (I'm not necessarily saying this is a valid concern, I just remember it being raised. I assumed that "shared nodes" would remind everyone of those recurring discussions - apparently, that wasn't correct.) >> - we don't have software support for it >> > you simply add area=yes to your closed way. Which won't be supported properly by renderers (for many highway types - and not at all for directional features like steps or oneways) or routing applications (it might use the outline of the area, which is equivalent to ignoring the area=yes). A simple area=yes could even be considered wrong. I'd interpret a highway=* area with area=yes is an area where there's no regulated direction of traffic. There should be an easy way to identify areas which are outlines of ways so you can decide not to draw these. After all, abstracting roads to lines with uniform, non-realistic width can be a sensible design decision. (See above.) Even if you believe it would be correct, there would still be problems with directional features, left/right/forward/backward tags etc. Therefore, I think this statement is very important: > The only thing: don't delete the > current centre-ways. Maybe it would be best to tag the road-areas as > landuse=road instead of highway=something to avoid conflicts. >> As the next step for areas where most of the basics are done, I'd rather >> start lane mapping. It has some very attractive use cases (detailed >> routing instructions for cars, routing and maps for >> pedestrians/bicycles) and it's relatively easy to gather the data (you >> just look at the street, no tools required - not even a GPS). >> > yes sure, but A doesn't exclude B. Not at all. I'm just stating my personal preferences. Of course, the perfect solution is to map everything. >> Actually, I don't believe most mappers will be able and willing to >> produce data that is more precise than what can represented with width >> tag + lane info any time soon. > > no problem, who wants to do it, can do it. Look here: > http://www.openstreetmap.org/?lat=51.300723&lon=11.427789&zoom=18&layers=B000FTF That's interesting! Luckily, a single example doesn't prove my "most mappers" statement wrong yet. ;) Tobias Knerr _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
