[OSM-talk] prohibited/restricted/priority and mandatory manoeuvres

[Peter Miller]

So we now have relationships to play with, which is just great. Now we need
to decide how to use them before we encode lots of data, and before people
start coding journey planners.

 

Currently we have a proposal of 'turn_restriction'. 

http://wiki.openstreetmap.org/index.php/Relationships

 

IMHO, I don't think the word 'turn' is correct, because we might be talking
about something that is straight-on, so the phase 'manoeuvre' is actually
the more appropriate Engish term (or actually probably the better French
term that has now been appropriated by the English from the spelling). Also,
the term restricted is not quite right. See below for how the other
standards use the phrase.

 

If one looks at other standards, such as GDF
(http://www.ertico.com/en/links/links/gdf_-_geographic_data_files.htm) or
the equivalent from the Ordnance Survey
(http://www.ordnancesurvey.co.uk/oswebsite/products/osmastermap/userguides/d
ocs/OSMM_ITN_userguide_v1.0.pdf) one finds that they tease out other
important different sorts of manoeuvre. There is also consistent terminology
between these standards (and GDF is now an ISO standard).

 

In these documents they identify the following routing limitations.

 

1) Prohibited_manoeuvre ; one that there is a not legal, but might be
physically possible (GDF and ITN).

2) Restricted_manoeuvre ; that that it is not impossible to make (often for
identified classes of vehicle) (GDF and ITN)

3) Priority_manoeuvre ; one that does not need to be announced as you are
following the same road. (GDF and ITN)

4) mandatory_manoeuvre ; one that you must make. (ITN only)

5) Finally, there is also a special type of prohibited manoeuvre with 'no U
turn' for dual carriageways. The actual encoding of the prohibition includes
three ways, the one on the initial dual carriageway, the short stub across
the carriageway and then the link on the other carriageway coming back
again. For this we would need to have three associated ways 'from' 'via' and
'to'. (ITN only)

 

For all of these above types, they can be restricted by time and by vehicle
class.

 

I propose that we use the above phases as appropriate in place of
'turn_restriction' and keep the 'roles' as described in the proposal.

 

If anyone is interested, there is a comparison between GDF and OSM here:

http://wiki.openstreetmap.org/index.php/GDF

 

 

 

Regards,

 

 

 

PeterIto

 

 

 

 

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