[talk-au] OpenStreetMap in Government

[David Bannon]

I am not sure I agree with you Waldo0000.. (???).

Its useful in my opinion when ever storing data (of any nature) to think
about how that data will be used. While we will often find other use
cases later on, addressing the primary one is important.

I think very few users of map data are prepared to, eg, install mapnik
or grep through the downloaded data relating to a particular road they
may consider using. Instead, they want to get a idea of just how
passable a road might be. They are asking a very subject question and
expect a subject answer.

They want to know if its a sealed or not. If not, they will ask if its
suitable for a conventional car, an SUV, a 4wd, a "blood and guts 4wd".
Armed with that info, they look at their own car and their willingness
to take risks and/or have some fun.

Thats all very subjective ! My point is, most of that process is, of
necessity, completely subjective, not just the tagging we are talking
about here.

The smoothness= tag ( http://wiki.openstreetmap.org/wiki/Key:smoothness
) tries to address this, but smoothness is quite often not the issue and
the values given to smoothness= are simple horrible (pun intended). (I
suggested, in the past, we should alias something like 'drivability' to
'smoothness'). Anyway, smoothness= has all those subjective problems,
its there and usable. If I could get over the idea of calling my
favorite tracks 'horrible', I'd use it !


So, at the risk of being called politically incorrect, I think we need
to collect data that can and will be used. 

David


On Tue, 2013-05-14 at 07:58 +1000, waldo000000 at gmail.com wrote:
> On Mon, May 13, 2013 at 9:37 PM, Steve Bennett <stevagewp at gmail.com>
> wrote:
>         
>         
>         Sometimes people think that it's better to slice up
>         information into
>         lots of little "objective" facts, like (in the case of
>         mountain bike
>         trails), width, surface, grade, etc, rather than a
>         "subjective" fact
>         like trail rating. But in practice, it's impractical to
>         collect that
>         much information, and it's impractical to combine it back into
>         a
>         usable form for data consumers, so we lose twice.
> 
> 
> The important point is that a subjective tag at least needs an
> objective definition. See e.g. the pretty good definitions on
> http://wiki.openstreetmap.org/wiki/Grade. The subjective tag
> "tracktype=grade1", according to the definition "Paved track or
> heavily compacted hardcore" could easily be replaced with the
> objective tags "surface=paved" or "surface=compacted".
> 
> 
> I would argue that entering objective facts (e.g. "surface=*" in the
> previous example) is a much better option than subjective tagging. It
> requires no more information than you already have, and is no less
> practical for data consumers. It's actually more powerful, specific,
> clear, verifiable (http://wiki.openstreetmap.org/wiki/Verifiability),
> and reduces the dependency of mappers and consumers on the wiki to
> make sense of the data.
> 
> 
> Point is: if you insist on using subjective tags as a short-cut,
> please, please at least ensure they have objective definitions in the
> wiki.
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