[R-sig-Geo] Calculating map orientations

[hadley wickham]

Hi all,

I was wondering if anyone knows how the default orientations are
calculated in the mapproj package.  I need this for
my ggplot2 package because when you are drawing maps with multiple
layers of data you (obviously) have to calculate the orientation over
all data, not just the data points in a single layer.  You can see
some of the problems I'm having at
http://had.co.nz/ggplot2/coord_map.html

I tried emailing the maintainer of the mapproj package but didn't get a reply.

Hadley

-- 
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