[Routing] generalized routing format - pre-computation
sascha-ml-gis-osm-routing at silbe.org
Sun Oct 19 00:49:36 BST 2008
On Sun, Oct 19, 2008 at 01:05:02AM +0200, Lambertus wrote:
>> Does gosmore check place=... areas to determine whether a way is
>> inside a built-up area to adjust the speed accordingly? In that case
>> I'll have to dig into the Gosmore source again to see how Nic got it
>> this fast. :)
> No, afaik Gosmore does not do that.
OK. That was what I asked about - those checks are quite expensive, so
I'm looking for ideas how to speed them up.
> And if appropriate maxspeeds are tagged then it won't need to.
I don't think we agree there - IMO default maximum speeds (e.g. 50km/h
inside cities) shouldn't be explicitly tagged. That's a different
discussion, though, let's have it on talk if at all. I'll just mention
that setting the default maximum speed for _cars_ as maxspeed=... means
entering wrong data for the other vehicle types: In Germany speed limit
signs within a built-up area may actually _raise_ the limit above
defaults for _all_ vehicle types.
> Perhaps you use this during namefinder lookups?
It's a simple yes/no check, no names.
> Gosmore doesn't use much ram while parsing the planet data so I'm
> pretty sure it will scale linear whatever the amount of data.
The amount of RAM used for temporary data is quite low, but the whole
database is mmap()ed into memory. I thought Gosmore does the same?!
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