3D rotation and graphics

[Hal Mueller]

I think you would be able to do this with Quartz Composer.  Generate 
your map as an image in a supported format, and then you can render 
it onto a horizontal surface ("billboard", in Quartz Composer 
terminology) with the pie charts floating above the appropriate 
locations.  You can change your viewpoint/rotation once the objects 
are in place.

Quartz Composer is installed as part of the Apple developer tools, 
which are free and included on the system disk, but which are not 
loaded onto your machine by default.

http://developer.apple.com/graphicsimaging/quartz/quartzcomposer.html

http://developer.apple.com/documentation/GraphicsImaging/Conceptual/QuartzComposer/qc_intro/chapter_1_section_1.html

-- 
Hal Mueller                hal at mobilegeographics.com
My Treo beat up your iPhone.