On Mon, Oct 20, 2008 at 10:31:35PM +0200, Nic Roets wrote:
During rebuild, gosmore only mmaps the wayType data which is roughly 1GB. During one stage, it iterates through the node data and update the wayTypesOK, so you don't index by location currently (since that would need bounding boxes)? How does your geocoder work? I.e. how does it find a given street inside a given town?they point to so that bounding boxes can be computed.
I don't believe that writing software for adjusting speeds for built-upIt may be a misunderstanding because of my choice of words (I'm not a native speaker) or there may be countries where it works differently. Since both are important for me to sort out, I'll explain how it works in Germany:places is worth all the effort. Reasons :
Each time you enter a town (or village or whatever), there's a yellow sign (StVO sign number 310 [1]). Exactly at the location of these signs the defaults change from 100km/h to 50km/h (for cars). This is regulated by law (Straßenverkehrsordnung (StVO) § 3 (3) [2]) The area delimited by these signs is called "Geschlossene Ortschaft" [3], roughly translated it would be "closed (=delimited) place (village)".
Mapping these signs a) is mapping what's on the ground b) is important for speed calculation during routing (see below)c) needs to be done with different tags since it's completely different from
- landuse=residential ("there are some residential buildings")
- place=town/... ("addresses within this polygon are part of town
XYZ")
- boundary=administrative ("this land (town+fields) is administered
by town XYZ")
Not having these polygons (and most often not even one of the others) is the number one cause for "bad" (=suboptimal) routes I've encountered. The router chooses the streets _through_ the city instead of _around_ it (most places with significant non-local traffic have "bypass roads" (Ortsumgehungsstraßen) that lead around town). As both streets are of equal quality (e.g. both are primary and 2 lanes per direction), it's only natural for the router to do so.
From my visits to Swiss and Austria, I had the impression it works very similar there (defaults changing at the town sign). So there's quite a large number of users affected by this (well, even if it were just Germany, it'd suffice :) ).
There area) other things besides default speed limits that change at said signs (e.g. use right lane vs. free choice of lane) b) other signs and facts that affect default speed limits (motorways, divided highway, ...)
How does it work in other countries? Are there different defaults and where do they change? What "prevents" you from driving as fast inside a town as you would outside?
[1] http://de.wikipedia.org/wiki/Bild:Zeichen_310.svg [2] http://bundesrecht.juris.de/stvo/__3.html [3] http://de.wikipedia.org/wiki/Geschlossene_Ortschaft CU Sascha -- http://sascha.silbe.org/ http://www.infra-silbe.de/
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