On 18-Feb-17 12:01 AM, Martin Koppenhoefer wrote:
2017-02-17 12:26 GMT+01:00 Simon Poole <[email protected]
<mailto:[email protected]>>:
Mistake #1: assuming that there is a vehicle class hierarchy (of
any kind).
well, that's what the wiki has in the sentence above the hierarchical
scheme (indentation): "This hierarchy is different in each country."
It might be different, but a hierarchy "of any kind" is likely to
exist in most countries.
Typically law-makers see no reason to conform to computer science
niceties when drafting regulations (rightly so) and will simply
add or deduct vehicle properties in ways that make sense for the
regulation in question (well most of the time :-)).
when it comes to signs with restrictions, drivers can benefit a lot
from a logical hierarchy, because it makes the signs quickly readable.
Otherwise you end up with signs like this:
http://www.laleggepertutti.it/wp-content/uploads/2014/03/cartelli-stradali.png
The OSM hierarchical approach makes sense from a practical mapping
pov, but will have issues accurately modelling such edge cases and
I would suggest just living with that.
I still believe we should know what the key "motorcar" is meant to
describe (it could also be a country specific definition, must not be
valid globally). There's no definition in the wiki, it only states
"automobile/cars" and a link to wikipedia which is more confusing than
helping.
What does it mean that the "motorhome" is indented in the wiki table
with respect to motorcar, while "goods" is not?
Do you then need a definition for trailer, hgv, etc? Where does it stop?
Dictionary motor car: a vehicle, especially one for passengers, carrying
its own power generating and propelling mechanism for travel on ordinary
roads
How do I know whether a restriction or allowance for motorcars is
valid for hgv as well? Or shall I add 33 access-tags on every road?
E.g. typically an isolated motorcar=no implicitly means also hgv=no,
goods=no, motorhome=no, agricultural=no, tourist_bus=no, bus=no, ...
while a motorcar=yes does likely not imply anything for hgv or
tourist_bus, but eventually it does for motorhome and goods.
motor_vehicle=no and than add any that are allowed .. e.g. goods=yes
and there must be a method of adding time restrictions to that too . eg
goods only between 19:00-22:00
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