[OSM-newbies] Trust GPS or Yahoo aerial imagery?

[Gervase Markham]

Rick Collins wrote:
> I very much disagree with this idea.  Existing maps and images are 
> not likely to be consistently off by a significant amount. 

What makes you assert that? I think it's eminently possible that the 
orthorectification or alignment of the Yahoo images is out by 10m. 10m 
is not very far, when you have to figure out exactly where a speeding 
plane or satellite which took the photos is.

They are also much more likely to be *consistently* off within a certain 
area than they are to be *inconsistently* off.

My GPS on the other hand, is an OpenStreetMap recommended model, and I 
was walking up and down the centre of the roads (not cycling or driving) 
with a clear view of the sky.

Gerv