Hi, It doesn't help so much on the precise point of rotation parameters. I've had the same problem few days ago, and despite many tests I didn't manage to get a proper rotated image. I fixed that with a "solid" rotation, set into the image file. But I'm also interested by that approach.
What are the units of rotation parameters ? I think it's radians, but maybe directly cos and sin of angle in radian which would be more adequate tu use in the six parameters transformation... Is it counter-clockwise (i.e. trigonometric) direction ? is the first one x or y rotation term ? The ESRI support page (http://support.esri.com/index.cfm?fa=knowledgebase.techarticles.articleShow&d=17489) is useless. the best info I've found are here : http://www.omg.unb.ca/~jonnyb/processing/geotiff_tifw_format.html but I haven't tried yet. Guillaume
