[Proj] Post-projection affine transformations?

[Michal Migurski]

Hello,

I'm trying to determine whether Proj parameters can express an arbitrary post-projection affine transformation, e.g. shear or rotation. I've looked at the +towgs84 parameter but this doesn't seem to be a good fit. Is it possible to transform a projection, for example to flip a mercator map upside-down? I'm rendering images with Mapnik which seems to use Proj internally.

-mike.

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michal migurski- mike at stamen.com
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