[OSM-talk] protocol for adding buildings using aerial imagery?

Frederik Ramm frederik at remote.org
Tue Dec 28 07:32:16 GMT 2010


charlie at cferrero.net wrote:
> This is a major issue when tracing tower blocks - the taller the 
> building the more the roof appears to be displaced relative to the floor 
> due to the perspective of the plane taking the photos.  I have always 
> tried to map the base because, ultimately, a map is a representation of 
> what's at ground-level.  If you mapped roofs you'd get very tall 
> buildings overlapping the surrounding roads.

Sometimes I map the roof to get a good idea of the shape, then move the 
result to match the base.

It would be interesting to have editor support for estimating the 
building height depending on that displacement, or depending on the 
extent of the shadow - that would have to be calibrated for each imagery 
and location of course but so does the displacement of the whole image, 
and we're seeing people working on the latter...


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"

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