[OSM-talk] tagging and rendering

[Dave Stubbs]

>
> I can see the attraction to the use of numbers for the values of the
> highway tag. Having a new system that does not use terms that
> have other meanings can force people to think about the OSM
> definitions of the values. The UK centric terms have this effect
> for me. I have to think about what motorway means for the US
> or Korea in terms of the OSM definition because I have no competing
> definition of the term motorway in my mind. For me motorway
> only has an OSM definition.
>
> People in countries with roads called motorways have a conflict
> in their minds. If a section of a UK motorway is a single lane
> dirt track then someone in the UK may be tempted to label
> it as a motorway because it has a motorway sign. (That's just
> a hyperbole to make a point. Let's keep discussions of the
> highway tag itself on a separate thread.)
>
> One solution to this psychology problem is to use terms
> that do not have a local meaning. Numbering might be
> one way to do that for some tags but not for others.
>
> Another way to solve this psychological problem is to hide
> the recorded data from the user. Something like presets
> was suggested. Having different terms being used by the
> person who writes the rendering rules and the person
> collecting the data might cause other problems.
>


There are some genuine problems that need solving -- tag translation,
tagging hierarchies, tag documentation and guides, and some "bad" tags
in common use to name but a few.

Unfortunately people seem most interested in solving these problems
via the magic bullet approach. This basically involves turning
everything on it's head, adding a level of indirection or two, putting
in some extra technical elements, and finally hoping that someone will
take the opportunity of the wholesale change to actually fix the
problem.

The highway tag has well known problems; mostly that it's a highly
subjective short cut for lots of tags and widely differing concepts,
of which nobody is entirely sure which takes precedence. This doesn't
get fixed by making everyone use numbers. Numbers are not an
intrinsicly better model of road types, nor do they make it easier to
create such a model.

Tags can be translated from English just as easily as they can be
translated from numbers. Presets can be created using english tags as
well as they can for numeric tags.

Numbers do not possess a natural hierarchy of feature types, nor do
they make such hierarchies easier to create.

Numbers are an abstraction, that's all they are. The present tag
names/values are also generally abstractions... just human readable
ones.

Dave

PS. This isn't aimed at anyone in particular, just a general observation.