[OSM-Talk-ZA] Tagging

[Nic Roets]

Hi Mark and Paul,

I guess our standards are a bit open to interpretation, which is not
necessarily a bad thing. It's relatively easy to get it right. It does not
work for Rossouw Street M13 which carries a lot less traffic than Louis
Botha M33. (And some idiot changed Hans Strydom in Pretoria to residential a
few weeks back !)

Paul, your system also looks easy except distinguishing between secondary
and tertiary.

I may be responsible for tagging the R104 as tertiary so that it stands out
a bit better between the the M2, M4 etc. But if someone wants to change it
(or and other road), I'll stick to the new values.

The only thing that is important to me is that most routing software
currently assumes that 'trunk' roads are faster than primary etc. And it's
unclear if pedestrians and bicycles are allowed on trunk roads, so explicit
tagging is best.



On Tue, Nov 4, 2008 at 2:29 PM, Paul van Helden <paul at planetgis.co.za>wrote:

> Hi All,
>
> I'm have a similar question to Mark's. The words "trunk", "primary",
> "secondary" and "tertiary" implies a functional classification. A
> functionally classified road network should have each class
> (more-or-less) forming a closed network. The "motorway" class is not a
> functional classification, but a physical classification. For me, using
> the "motorway" class is acceptable because that is the way street maps
> are typically made: showing dual carriageways as the top class
> regardless of route designation or function. Anyway, only rarely in the
> case of underutilized dual carriageway roads is that an incorrect
> assumption.
>
> Defining "trunk" as N roads is making it a network classification. Since
> trunk roads are rendered in green and we want to see the national
> network on the map, regardless of function, it works.
>
> We have (at least) 3 different ways of classifying roads and these need
> to be blended into one classification. Our problem is also that we have
> to use the existing classes and get the OSM map to look like the street
> maps we are used to in SA. (In terms of colouring & the scales at which
> they display).
>
> The "tertiary" class is not mentioned on the tagging standards page. Yet
> there are a lot of them, many which (like trunk) "looks" right.
>
> My suggestion is to define the tag names as follows:
>
> Any freeway = "motorway" (physical classification)
> N roads (undivided) = "trunk" (network classification)
> Major routes linking into freeways and N routes, typically low numbered
> M & R = "primary" (main roads: combination between functional and
> network classification)
> Important routes linking into "primary" (main) roads (this sometimes
> will be a road without a R designation) or routes linking up populated
> places = "secondary" (network classification)
> Local collector roads, ie. residential roads that carry through traffic
> (often residential roads with sidewalks) = "tertiary" (functional
> classification)
> The rest = either "residential" or "unclassified".
>
> In terms of the correct naming of the above (for legends on customized
> maps) I would go for:
>
> Freeways
> National roads
> Main roads
> Secondary roads
> Collector roads
> Residential / other
>
> My suggestion for "tertiary" will invalidate many of the current
> "tertiary" roads - those that are not residential and are connecting
> populated places. A good example is the R104: Pretoria street connecting
> Bronkhorstspruit parallel with the N4.
>
> http://www.openstreetmap.org/?lat=-25.7542&lon=28.4227&zoom=13&layers=B000FTF
>
> Comments?
>
> Regards,
>
> Paul.
>
>
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