[Routing] Default speed limits / built-up areas (was: Re: generalized routing format - pre-computation)

[Marcus Wolschon]

On Tue, 21 Oct 2008 13:28:38 +0200, "Nic Roets" <nroets at gmail.com> wrote:
> On Tue, Oct 21, 2008 at 11:52 AM, Sascha Silbe <
> sascha-ml-gis-osm-routing at silbe.org> wrote:
> 
>> 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
>>> wayTypes
>>> they point to so that bounding boxes can be computed.
>>>
>> OK, 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?
>>
> 
> You type the name of the town, click to center, then type the name of the
> street. The nearest occurrence will be the first result, so clicking on
it
> will take you there.
> 
> Implementation : Each wayType has a center point and zero or more "tag
> values", for example the name. There's an alphabetical index of the names
> as
> well as a complicated algorithm for handling the case where two tag
values
> are equal by finding the nearest occurrence.
> 
> 
>>
>> 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)".
>>
> 
> Then the way should be split where these signs occur and the max_speed
tags
> set explicitly.

You don't set maxspeed-values for default-values.
There have been lengthy discussions about that and
this is what was agreed on.
You have default-values documented in the wiki in
a machine-readable format for each country. It 
depends on the type of vehicle, the value of the
highway-tag and the fact that you are inside or
outside a closed city.

Marcus

> The US makes up more than half of our "planet". If you consider that the
US
> population more than doubled during the 20th century, you realize that
the
> majority of US town planning took place after the invention of the
> motorcar.

The US is an outdated piece of imported data that very, very slowly
gets corrected by way too few people.
If you want growth done by mappers, look at asia or europe.
It is not representative for how things need to be done to correctly
reflect
all situations everywhere in the world.

> This means you often get stretches of highway / motorway inside cities
with
> large shoulders, embankments and railings so that it's safe to drive
there
> at high speed.

Well, these seem to be single roads that get their own maxspeed-tag anyway.
Do you have no general speed-limit on all roads inside the town this is in?
If a single driveway has no maxspeed-tag, am I allowed to drive there as
fast
as I can?

Marcus