[Talk-ca] Canadian imports: good or bad?

[Bégin, Daniel]

Steve, Paul,

I was on the impression that the consensus was more about using Canvec where it is the best available source and, when it is not, the data could be imported, but only after an exhaustive verification using available data/imagery.

Whatever is the consensus, it should be documented in the wiki.

Furthermore, I think that "internal consistency/accuracy/existence" should be defined...

consistency: ? 

Accuracy: Bing imageries in urban areas are pretty good and easy to correct, if necessary, using available GPS tracks. It is not the case outside these areas.

I suspect that Bing imageries are not always corrected using a good digital elevation model. It means that in hilly areas, the image shows an object somewhere on the ground while the object is actually somewhere else, due to Z distortion.

Existence: Again, outside urban areas, the resolution of Bing imageries doesn't allow for detailed validation. You won't be able to see small objects, even if they are there!

Best regards,
Daniel

-----Original Message-----
From: Steve Singer [mailto:steve at ssinger.info] 
Sent: April 25, 2012 07:12
To: Paul Norman
Cc: talk-ca at openstreetmap.org
Subject: Re: [Talk-ca] Canadian imports: good or bad?

On Wed, 25 Apr 2012, Paul Norman wrote:

>> 2. There is not a consensus among the community that CanVec data can 
>> be imported without verifying the data for internal consistency and 
>> where possible against imagery.
>
> If no one disagrees with the fact there is not a consensus that 
> importing CanVec without minimal verification is acceptable I'll go 
> ahead and document on the Wiki, using Andrew Allison's examples.

+1.

Is there enough support to use the positive rather than the negative language, ie 'There is consensus among the community that Canvec data should only be imported when the data elements have been verified for internal consistency/accuracy/existence with the available imagery'

Steve


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