[mkgmap-dev] OT - Access/Turn Restrictions

Sun Mar 1 18:19:58 GMT 2009

Hi Wolfgang,

On Sun, 1 Mar 2009 12:32:39 +0100
"Wolfgang v. Hansen" <wvhansen at fom.fgan.de> wrote:

> On Sat, 28 Feb 2009, Mark Burton wrote:
> 
> > I do not know if garmin supports restrictions that are only in force 
> > during certain hours. I have carried out web searches and found nothing 
> > so far on that subject. If we had an example map (unlocked) that 
> > contained an example of such a restriction we would have a chance to 
> > reverse engineer it.
> 
> Well, there is an example: The Sierichstraße in Hamburg is a one-way 
> street where the direction of traffic changes daily at 4:00 and 12:00. 
> Garmin respects this with City Navigator as I have just tested.

That's very interesting. So we know it can be done. However, unless we
can see the restriction record and learn the magic, it's going to be
difficult to achieve.

> Swiss mountain passes might help as well to understand the mechanism as 
> they are blocked in Winter and disallow routing.

To me, that implies that the timing information is likely to be
specified in additional fields being added rather than setting values
within the existing record because there isn't a huge amount of space
in the records that we don't understand the purpose of fully (3 bytes).
That isn't enough space to be able to specify an active/inactive time
that can be in a range of hours (probably minutes) to months.

Hmm, we need an unlocked example.

Another thing, mapsource doesn't seem to show the restrictions so you
can't query them. Does mapsource show the timed restrictions you
mention above? For that matter, does the gps show them in any way?

Cheers,

Mark