I do not have access to the tools in question at the moment, but it cannot be a projection issue unless there's a bug in the software.
My best guess is you are not using the same ellipsoid or datum as your reference chart. Also keep in mind that 30nm is only a 2.5% error (assuming they are supposed to be tangent at exactly one point) so a lot of factors could be involved, and not just with your chart.
If you can pass me the projection, datum and ellipsoid data you have used, and the coordinates of the origin point for the circles as well as the coordinates of a point in the circumference on the, for example, 360, 090, 180, 270 radials, I'll have a check and see if they come up to what they're supposed to be.
Last edited by LH2; 19th January 2008 at 17:50.
Reason: zpeling