[OSM-talk] When mental models go wrong: OpenStreetMap

[Lauri Hahne]

First, I must admit that the subject of this message is a little bit
outre but don't let that bother. *

I'm trying to summarise a few things I've been thinking lately. I
think none of these issues is major or something that should actually
be worked on. I have no suggestions what-so-ever what could fix the
issues but don't let that bother. I just want some feedback and to
know whether anybody agrees with me.

1. Ways

- There are one kind of ways in the database. Ways can have attributes
(tags) but aren't required.
- The tagging scheme suggest there are many kinds of ways (highway,
cycleway, aeroway...)
- Potlatch and JOSM's preset (and mappaint?) system allow you to pick
a type for way.
- We have questions such as "how can I turn this way into a bridge" or
"how can I create a "bridge-way" at #osm once in a while.

This leads me to think that do Tagging Scheme, Wiki, Potlatch, and
JOSM (in that order - ordered by "severity") give wring kind of hints
what's actually in the database. This is because it has become pretty
obvious to me that there are people (likely not much?) who think the
that we have different kind of ways. These people need to be told that
we don't have different kind of ways but way which have attributes. I
can see why these people think like this because especially wiki does
list different kind of ways in the Map Features page.

2. Nodes

Apparently Potlatch tris to keep nodes and POIs separate even though
these are the same thing again. This works really well in Potlatch but
yet again it's against our data model and might lead to some
confusion. I haven't seen any examples of this so this is very
theoretical for now.



As I wrote earlier, I have no suggestions about "fixing" these issues.
IMHO the current data model is great but I think it should be made
obvious to newbies. One way to do this would be to introduce OSM as
trace-nodes-way-tags instead of the traditional trace-nodes-way which
is quite prevalent in slides etc. It would also be a nice idea to
write an introduction to our data model and put it in the beginning of
the Beginner's Guide in Wiki. I'm volunteering to write this if
somebody promises to proof-read it.


Ps. As the beginning of this mail suggests, I had no purpose to write
the paragraph about suggestions but it became imminent that this post
needed something in addition to just listing some weird stuff.


* http://www.crc.ensmp.fr/~besnard/Publications/Besnard-Greathead-Baxter-2004.pdf

-- 
Lauri Hahne