[Talk-ca] cleaning up after the GeoBase import

[James Ewen]

On Thu, Jun 11, 2009 at 2:40 PM, William Lachance<wrlach at gmail.com> wrote:

> I have to say that as someone who uses OSM data in my own projects, I
> really don't like the idea of creating our own "OSM-CA" mapping and
> tagging conventions. Do we really want to be formatting our OSM data
> differently from international conventions?

We will be using standard conventions, but there will be extensions
that are unique to Canada, or possibly shared with a few other
countries. I highly doubt that there will be many ice bridges and
winter roads in places like Costa Rica, and Ethiopia.


> This basically amounts to
> asking everyone who writes tools/products that read/write OSM data
> (which go far beyond the OSMARender and Potlatch editor, see for example
> the developer tools at http://cloudmade.com) to accomodate us.

Well, if you can glean from my writings the concept that I was
attempting to communicate, you would understand that the suggestion
that I made would work with existing OSM data, as well as with the
GeoBase sourced data. The GeoBase data just magnifies the effect
because of the much higher degree of way fragmentation.

With existing OSM sourced data, if I want to change a tag on a roadway
that is made up of 3 segments, due to a bridge in the middle of the
roadway, I have to select and change the tag on each of the 3
segments. I am simply suggesting that the editing software be made a
little smarter in that it would be able to follow the selected tag
information, and allow you to change all the adjoining segments that
have the same tag value. This would work very nicely with the existing
data, and for the GeoBase sourced data, it would work the same, just
that there would be more segments in the data.

If I were to take a 200 metre long section of roadway, and define it
using "International Conventions" within the OSM structure, it is very
possible that I could have a bunch of segments, where perhaps the
number of lanes change, the surface type changes, a bridge exists, and
just for fun, it becomes a one way street. If each of these segments
has a road name associated with it, the renderer can end up placing a
bunch of names along that section of street. If however the renderer
were instructed to look for all the segments with the same name, and
only place a single name on that section until XX distance away, it
would make the map look better.

When I map a roadway, I tend to make it one long way, from start to
finish unless I have to break it to allow me to tag something
specific. I have created highways that are hundreds of miles long as a
single way from a GPS trace. I have to break them to convert, but then
I stitch them back together afterwards. So, when I look at the
finished product, there's usually a label somewhere along the length
of the way... sometimes a couple as you move along the length of the
way. Because GeoBase segments the data much more, we see what I would
consider deficiencies in the rendering. My original idea of changing
the data to suit the renderer was against the mantra, but I was trying
to hide the fact that that was indeed what I wanted to do...

James
VE6SRV