[OSM-talk] tagging trailblazes / marked paths

Andy Allan gravitystorm at gmail.com
Wed Aug 6 00:23:19 BST 2008


On Tue, Aug 5, 2008 at 9:40 PM, Alex Mauer <hawke at hawkesnest.net> wrote:
> Frederik Ramm wrote:
>> I've never been a friend of that voting business but it seems to get
>> more absurd every day. Is it perhaps time now to have a vote on
>> abolishing votes altogehter - or should we continue to let people vote
>> on whatever they like and ignore the results?

Hmm. It's a tough one, especially when 34 people (out of an electorate
of, lets say, the 5,750 people editing last month) only narrowly agree
on restructuring some of the most widespread tags in the db. The wiki,
for better or worse, is most likely seen as authoritative by most of
those 5,750 people and so I'd like it if everyone was a bit more
cautious about changing what's said on there, especially when it comes
to changing existing conventions/features, posting stuff that's
contrary to established use, or confusing or complex topics.

> I like Andy Allan's modifications to the Key:crossing page, suggesting
> that it be used for documenting current usage, with renderers working
> from that.  So all you have to do to add a key or value is to use it.

It's the way I like it, although the downside is that I'll often start
tagging and rendering new stuff and forget to document it (or even add
it to the key)

(Ahem. Notice is hereby given that tagging cafes with "fryup=yes" is
likely to get you a nice fork-in-a-sausage symbol on the cycle map :-)
http://www.gravitystorm.co.uk/osm/?zoom=16&lat=6711490.40418&lon=-11750.44101&layers=B00
)

> It's unfortunate that current usage is so hard to find, particularly
> outside of Europe...

If anyone needs some real figures for these discussions, I'm more than
happy to help. I only realised recently that tagwatch only covers
Europe, which is unfortunate. So below is the list of ways using the
highway tag with more than 100 instances. You can see that the
highway=footway/cycleway/bridleway/pedestrian totals 509,920 instances
(path has a respectible, but tiny by comparision, 2165). And everyone
should remember the 509k instances mean that *lots* of different
contributors use these tags and understand them; and there are *lots*
of renders, routing algorthims and whatnot understand and use them
too.

So what are the advantages of the change? One scheme that covers the
corner cases along with the most common occurences. And the
disadvantages? Confusion for many contributors, every data user
needing to understand two sets of tagging styles, the most common
cases (the 509k) needing twice as many tags as before, and the corner
cases are still fairly corner needing a small handful of tags. So in
my opinion, the problem is the main tagging scheme wasn't well enough
documented (a canal towpath is hardly a pedestrian precinct, which I
came across today) to prevent arguments and misunderstandings, but the
proposed upheaval and/or dual tagging regimes is overkill. A way to
tag the corner cases that don't fit in well would have been much
preferable. And you can throw in the term "cost/benefit" here as well,
but I'm sure everyone gets my point by now.

Cheers,
Andy

 residential                                              | 12605937
 service                                                  |  2200128
 unclassified                                             |  1088886
                                                          |   529868
 secondary                                                |   510636
 track                                                    |   417479
 tertiary                                                 |   391691
 footway                                                  |   320536
 primary                                                  |   268507
 motorway_link                                            |   181060
 cycleway                                                 |    97914
 pedestrian                                               |    84164
 motorway                                                 |    81050
 trunk                                                    |    70124
 trunk_link                                               |    27778
 primary_link                                             |    20594
 steps                                                    |    19919
 living_street                                            |    13936
 road                                                     |     8500
 bridleway                                                |     7306
 unsurfaced                                               |     6313
 minor                                                    |     4010
 path                                                     |     2165
 construction                                             |     1675
 FIXME                                                    |      889
 secondary_link                                           |      738
 byway                                                    |      630
 footpath                                                 |      324
 proposed                                                 |      277
 bus_guideway                                             |      133
 stub                                                     |      120




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