[Community] rotating a layer

[Jaakko Salli]

Hi Andrea,

On 25.7.2010 19:58, iomeneandrei wrote:
> 
> only for confirmation: is it impossible to rotate a layer with shapely?
> 

AFAIK 2D matrix transformations (rotate, scale,
etc.) are missing in the underlying GEOS library
that the Shapely uses. Personally I have needed the
transformations and have been doing them manually -
that is, applying the rotate and scale formulas on
the individual points of a polygon and then re-
constructing the polygon. This is not a quick operation
in pure Python and I assume that it should be much
faster when using GEOS with C/C++ (where you may have
direct access to polygon point).

Regards,
  Jaakko