> Date: Wed, 12 Nov 2003 19:49:32 -0800 (PST)
> From: Eric Choate <choatune@...>
>Subject: Plate Tectonics and Lat/Long boundaries
>
>Yeah, it's slow enough that we probably won't notice, but if the
>Americo-Canadian border is actually the 49th parallel

For more reading about the Canada/USA borders, look at the
International Boundary Commission website:
http://www.internationalboundarycommission.org/

The Canada-USA border, between British Columbia in the west and
Ontario in the east, runs 'along' the 49th parallel, but is
not defined by the position of "49 North".

The Canada/USA border is defined as a series of straight lines between
border monuments, and along the 49th parallel the monuments that are
located 'close' to whole degrees of longitude(e.g. monuments 489 and 490,
'at' 107W) are not actually located at 49 degrees north, when referenced
to the WGS84 datum. In fact, the border zig-zags back and forth above
and below 49N(WGS84), which is why if you look at the Degree Confluence
Project website you'll see some of the confluences 'belong' to Canada,
some to the USA.

Here's an image(30KB) showing the relationship of the border monuments,
and the border, to 49 degrees north:
http://members.shaw.ca/canmapinfo/temp/49thborder.png

--
Dave Patton
Canadian Coordinator, the Degree Confluence Project
http://www.confluence.org dpatton at confluence dot org
My website: http://members.shaw.ca/davepatton/
Vancouver/Whistler - host of the 2010 Winter Olympics