John, > The gnomon on your dial is a verticale pin at the center of the cross, > and half as tall as the cross, right?
Not sure which case you mean. In the polar-axis case, you're making a Horizontal Dial. The gnomon climbs at an angle from the centre of the dial (the centre of the cross). It you tell the application that the gnomon has some width, it assumes it is a trianglular profile cut from a flat plate and displaces the hourlines accordingly. In the case of the Upright, it is an azimuth dial. I assume a round pin centred over the cross. If you tell the application that the pin has some diameter, it displaces the hour lines so that the the leading edge of the shadow marks Time. In either case the height of the style is up to you. It needs to climb high enough to ensure that a shadow reaches across the time scale year round. That would depend on your latitude. My code doesn't attempt to work out how high it needs to be...but if anyone can tell me the maths of it I'll happily add an extra facility to the code. The cross is just there to mark the centre of the dial. I use a big cross rather than marking a single point in order to have lines running at right angles. That way you can use the lines, which should be the same length, to check the aspect ratio of the printed drawing. Cheers, Steve
