[Talk-ca] CanVec misalignment? Ottawa end of Portage Bridge
richard at weait.com
Tue Jan 1 16:49:35 GMT 2013
On Tue, Dec 18, 2012 at 11:30 AM, William Rieck <billr at thinkers.org> wrote:
> There is no gospel, although surveys and GPS traces may be close, but
> certainly not Bing and CanVec imports.
> The map should represent what you see on the ground, so make whatever
> adjustments are needed, using deduction from your primary source (a
> survey), that aligns with traces (absolute position) and any other sources
> (Bing, Canvec) if they are helpful.
Indeed. Consider all of your available sources. Part of the fun of
mapping is learning 1) that all of your sources are lying to you, and 2) in
what ways they usually lie. :-)
So when none of your sources agree perfectly, mappers have to make the best
informed guess that they can make.
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