[OSM-talk] tagging trailblazes / marked paths

[Andy Allan]

On Wed, Aug 6, 2008 at 6:43 PM, Alex Mauer <hawke at hawkesnest.net> wrote:

> In fact, highway=path makes it easier on renderers.

That's a bold statement for someone who has no experience running a renderer.

> Without using highway=path, renderers need to understand every single
> specialized way.
[...]
>  Most renderers can render all paths generically.  If a new access
> method is added, no change is needed.

What an absolutely terrible idea. This is astounding daft. If I have
chosen to render paths for cyclists, horse riders and pedestrians on
my map, why on earth would I want to accidentally render every other
variant when someone adds it? If I wanted to render every possible
future linear feature without knowing what it was I would use an
elsefilter on planet_osm_line and be done with it.

> Specialized maps like cyclemap
> only need to add special rendering for their area of interest.  For
> example, a cycle map can render any highway=path the same, and only
> highlight those which are for bicycles.

Specialised maps, nay, every map would need to keep track of every
single possible tag that you can add to highway=path just in case
someone adds something new that you don't want to render, or you
thought was dangerously misleading.

There's good reasons why every new feature gets a new tag - it's so
that you don't end up accidentally rendering things in a confusing
manner. There's very little to be gained from lumping lots of things
that you'd never want to render identically - no sane map would render
cycle paths, footpaths and snowmobile-only trails identically. So what
you're suggesting actually *raises* the bar for renderers since it's
now twice as hard to render just footpaths.

> 1. highway=[anything]way.  Renderers need to know about every type of
> [thing]way. Impossible to tag a multiple-use way (or ridiculously
> complex anyway -- highway=bicyclefoothorseskisnowmobileway?

I'm not going to waste time discussing with someone who can't refrain
from adding strawman arguments to everything he discusses.

So in summary - regardless of the discussions of whether the tagging
scheme is better for the contributor, or from a data correctness point
of view, please don't start bandying around wild statements about it
being "easier on renderers".

Cheers,
Andy