And don't forget about:
http://www.internationalboundarycommission.org/products.html#coordinates
Best Regards,
Brent Fraser
On 9/18/2012 6:17 AM, Connors, Bernie (SNB) wrote:
Hello Clifford,
I am a surveying engineer and I recall one of my surveying professors
telling us about the surveying of the Canada-US border along the 49^th
parallel. Below is a snippet from Wikipedia
(http://en.wikipedia.org/wiki/49th_parallel_north) that explains what
I recall my professor told us, but in my own words, the surveyors in
the 1800's could not measure accurately enough to place the boundary
monuments exactly on the 49^th parallel. Both countries have agreed
to accept the location of the original boundary monuments as the
international boundary. The info below from Wikipedia indicates some
monuments up to ½ mile from the 49^th parallel.
Parts of the 49th parallel were originally surveyed using astronomical
techniques that did not take into account slight departures of the
Earth's shape from a simpleellipsoid
<http://en.wikipedia.org/wiki/Ellipsoid>, or the deflection of
theplumb-bob <http://en.wikipedia.org/wiki/Plumb-bob>by differences in
terrestrial mass. Although the surveys were subject to such
limitations of early to mid 19th-century technology, extremely
accurate results were obtained. However, in some places the surveyed
49th parallel is as much as several hundred feet from the actual
geographical 49th parallel for the currently adopteddatum
<http://en.wikipedia.org/wiki/Datum_%28geodesy%29>,WGS84
<http://en.wikipedia.org/wiki/WGS84>. TheDigital Chart of the World
<http://en.wikipedia.org/wiki/Digital_Chart_of_the_World>(DCW), which
uses the Clarke 1866 ellipsoid, reports the border on average at
latitude 48° 59? 51? north, roughly 270 metres (886 ft) south of the
modern 49th parallel. It ranges between 48° 59? 25? and
49° 0? 10? north, respectively 810 metres (2,657 ft) and 590 metres
(1,936 ft) on either side of the average. In any case, the Earth's
North Pole moves around slightly, notionally moving the 49th and other
parallels with it; seepolar motion
<http://en.wikipedia.org/wiki/Polar_motion>.
As per treaty, lines between original established monuments (1861) are
straight lines on the chord, rather than curved lines on the tangent,
which generally keeps the boundary some distance from 49 degrees north.
In 1909 the United States, United Kingdom and Canada signed and
ratified a treaty confirming the original survey lines as the official
and permanent international border. Nevertheless, the difference of
the survey from the geographical 49th parallel was argued in front of
theWashington Supreme Court
<http://en.wikipedia.org/wiki/Washington_Supreme_Court>in the case
of/State of Washington v. Norman/, under the premise that Washington
did not properly incorporate the portions of land north of the
geographical 49th parallel, as laid out by detailedGPS
<http://en.wikipedia.org/wiki/Global_Positioning_System>surveying. The
court decided against the premise, ruling that the internationally
surveyed boundary also served as the state boundary, regardless of its
actual position.
Bernie.
--
Bernie Connors, P.Eng
Land Information Infrastructure Unit, SNB
bernie.conn...@snb.ca <mailto:bernie.conn...@snb.ca>
*From:*Clifford Snow [mailto:cliff...@snowandsnow.us]
*Sent:* Tuesday, 2012-09-18 00:16
*To:* talk-ca@openstreetmap.org
*Subject:* [Talk-ca] (no subject)
I'm doing some work in the Washington State and noticed some problems
along the border between BC and Washington State. I asked for help on
the talk-us mailing list.
I originally though the border was incorrect. However, because the
border doesn't track exactly along the 49th parallel there appears to
be some administrative areas that don't match up with the actual
border. See
http://www.openstreetmap.org/?lat=48.9803&lon=-121.7579&zoom=12&layers=M
Paul Norman wrote:
On Mon, Sep 17, 2012 at 5:49 PM, Paul Norman <penor...@mac.com
<mailto:penor...@mac.com>> wrote:
The survey points are based on IBC data (which they view as PD) and
are supposed to be accurate within a few cm and the limits of NAD83 to
WGS84 conversion (a few more cm).
I've verified a few by the lower mainland with survey and against a
few sources of accurate imagery and their data seems accurate within
the limits of the imagery.
You can see a clearing along parts of the border in that area so it's
accurate to within 20 meters.
I know that Washington State argued that they were not responsible
for the border costs in Blaine because it was not part of the
state since the state ended at the 49^th parallel and the border
is north of the 49^th there.
What I'll do is go and eliminate duplicate border ways, like I did
with the lower mainland.
There is a large multipolygon with a source of "CanVec 6.0 - NRCan"
that should probably extend to the border. However I'm not sure. I'm
wondering if anyone in Canada could investigate. The area is defined
as natural=wood.
BTW - I'm using USDA National Forest Services Topo Maps to add in
rivers, streams, etc. I see streams coming into the US from BC, but we
don't have any corresponding stream in Washington.
Clifford
I have promised to cut down on my swearing and drinking, which I have.
Unfortunately, this has left me dim-witted and nearly speechless.
Adapted from /The Lion/ by Nelson DeMille
-or-
If you can't explain it simply, you don't understand it well enough.
Albert Einstein
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