[Talk-ca] Missing harbours and marshes - L Ontario

[James A. Treacy]

On Thu, Aug 18, 2011 at 07:07:37PM -0700, Adam Dunn wrote:
> I've done a cursory examination of the Oshawa Harbour, and it would
> appear that there are two ways defining the water's edge:
> 1.) a PGS Coastline import, which is tagged as natural=coastline,
> 2.) a Canvec import, which is tagged as natural=water, and is part of
> a multipolygon relation, tagged with natural=water.

As the US edge of the Great Lakes are tagged as natural=coastline I
believe that all the Great Lakes should be tagged this way. There are
a few reasons for this:

1. it makes the lakes consistent as it only leads to confusion if the
US side is defined one way and the Canadian side is defined another.
Luckily, the renderer has hacks to deal with this sort of thing so it
currently works.
2. Large multipolygons can be very difficult to modify. Imagine
if there are changes to the coastline (especially when lots of
islands) due to updated data and the new multipolygons from canvec
don't have the same borders. Nightmare.

Lake Huron has already been converted to using the canvec data and
only uses coastlines. I am about 2/3 of the way done with converting
Lake Erie(*). If no one else is working on Lake Ontario, I will start
that when I'm done with Lake Erie.

(*) It is very fast as there are few islands. I spend 8 times longer
making fixes to the roads uncovered by the validator than I do on
the coastline. On the other hand Lake Huron had > 10000 islands and
took over a month.

-- 
James (Jay) Treacy
treacy at debian.org