[Talk-ca] Highways in Yukon

James Ewen ve6srv at gmail.com
Fri Mar 12 02:59:25 GMT 2010


On Thu, Mar 11, 2010 at 7:18 PM, Richard Weait <richard at weait.com> wrote:

>> One has to think about how the final map is going to be displayed.
>
> Now that is a little close to tagging for the renderer.

Yes, but I've been chastised about that statement before... we are not
tagging incorrectly to simply work around the renderer rules, but
rather tagging as to road classification importance, which the
renderer simply renders differently. If the data stored in the OSM
database is not useful to the user, then it may as well not be
included.

Back to my GPS... the major roads in the TeleAtlas database cause
routing problems. The routing routine will take me on a 350 km detour
just to stay on highways, rather than a 200 km direct route on what it
considers a major road. These major roads are indistinguishable from
the highways as far as physical features are concerned. Speed limits
are also identical.

I'd prefer to have these major roads promoted to the same
classification as the highways (in fact they are highways of the same
classification as the others)... as a side effect, the renderer in the
GPS would end up showing these roads that were previously not visible.

Just because the renderer changes the display doesn't mean that I am
specifically trying to misrepresent the road for the renderer.

The renderers take the tags we use into account when deciding on how
to display a way, so it is only appropriate that we also take into
account how the renderer will display the tags we are deciding to use.

It would be inappropriate to tag a stream as a coastline just to get
it to show up on a wide area map... it is however appropriate in my
opinion to tag an important major road (read only road) across a large
expanse of territory at an appropriate classification level, despite
what the rendering engines will do with it.

The database and renderers are pretty much married to each other.
Without the database, the renderers are useless. Without the
renderers, it's pretty hard to visualize the data.

James
VE6SRV




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