[Talk-ca] ACQTECH vs. Valdate vs. OSM User imput for CanVec HD

simon at mungewell.org simon at mungewell.org
Thu Mar 12 15:29:37 GMT 2009


> Hi, i have an area, which i found interesting.
> The York Creek (river) ish..

Are you perhaps refering to this spot?
http://www.openstreetmap.org/?lat=49.58793&lon=-114.5186&zoom=17&layers=B000FTF
http://www.flickr.com/photos/24244464@N03/2777260804/in/set-72157606820699424/

Where I sat with my doggie, having lunch on a fine afternoon last summer.

Looking at the sources available to me (OSM, OSM-GPX, CatMP and Canvec),
it appears that the Canvec waterway (coded 1470171) is about 15m too far
west.

That said, consumer GPS is not going to be very accurate. Look how the
(only!) GPX track is very noisy here. The only real way is to get multiple
GPS tracks going through the area an visually average/discount them to get
an approximately true location.

One thing that we have on our side when looking at waterways, is that
water is lazy and will take the easy route. So if you look at this area
with a contour layer you might be able to confirm which of the waterways
is in the wrong place.

Cheers,
Simon.





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