[OSM-newbies] Trust Yahoo or OSM?

[Dave F.]

Kevin Samples wrote:
> Be aware that buildings may appear to be shifted in comparison to the 
> Yahoo aerial images or any aerial imagery, but actually are not.  In 
> aerial photography any structure that has hight will exhibit parallax 
> (sometime drastically) and will appear to be tilted away from the center 
> of the image (central perspective).  If buildings are drawn from any 
> aerial photograph, the building should be traced from it's base where it 
> has contact with the earth in order for it to be properly aligned on the 
> map.
>
> Kevin
>   
I concur with Kevin - make sure you're not sketching the roof of tall 
buildings.
Another thing I've come across is where the shadows these high rises 
cast have been sketch as a part of the building.
Personally  I only map entities I'm familiar with so I have a rough idea 
of the floor plan.

Dave F.