[OSM-talk] Highway tags and other junk
guy at graviles-reynolds.org
guy at graviles-reynolds.org
Fri Dec 15 04:28:17 GMT 2006
Having read through your email and looked at the tracktype proposal, it occurs
to me that you are possibly thinking about this too much and form an even more
local point of view than even being UK centric.
Starting from the top, the road designations Trunk, Primary, Secondary,
Tertiary, Unclassified and Track ( I am ignoring motorways as a special case
and residential as these are ineffect unclassified roads with pre-applied
residential abbuters) are political/usage definitions which once described the
way roads were used but are now used for social engineering, in order to
enforce preference to one road over another. One only has to look at the road
numbering history around Baldock, to see this. It is this enforced preference
information that has to be mapped in the first instance.
These designations however bear no relationship to the physical nature of the
roads, they are there to enforce preference, arguing road designations on
grounds of their physical nature is verging on rediculous, shows localised
thinking in extremis and goes against what people are trying to achieve with
regards to traffic management by means of these designations.
Travelling around the globe, I have driven on many roads which have been
designated as 'Trunk Roads' but which ranged from 8 lane highways with hard
shoulders, through dual carriage ways, single lane roads with passing points
and on down to a line of poles marking a route across a desert. In the last
instance getting out the vehicle to measure the width of the road to ensure it
was of a certain type would have been a bit pointless (>1000km?).
The important thing was that these were all trunk roads, thus need recorded
same fashion and be given the same basic rendering on a map. However but this
needs then to be augmented by additional keys describing the width, surface
type, verges, hedges, fences etc and minor changes to the rendering. Whilst
this leads to a single highway having, a large number of additional property
tags which have to be labouriously keyed in for each way, it gives the freedom
to describe the exact nature of the highway. Whereas grouping the properties as
you have done with tracktype restricts the variants to too few, which are
potentially only capable of describing the tracks in your locality in the UK,
let alone all the highways around the world.
When it comes to measuring width, if there is a very tight restriction then
will often be signs giving the width, otherwise from my point of view giving
the number of lanes is sufficient and this can be done without the need to
leave the vehicle.
Guy
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