[Talk-ca] (no subject)

[Brent Fraser]

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.connors at snb.ca <mailto:bernie.connors at snb.ca>
>
> *From:*Clifford Snow [mailto:clifford at snowandsnow.us]
> *Sent:* Tuesday, 2012-09-18 00:16
> *To:* talk-ca at 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 <penorman at mac.com 
> <mailto:penorman at 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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