I am trying to create logarithmic spirals for illustrating many of the spirals in nature, but I am having a hard time translating from the "divergence" to any meaningful factor used to specify the spiral. If Divergence =1 it expands in equal increments, but what is the definition of Divergence = 2 or any other amount? I was hoping it would produce a logarithmic spiral (increasing by the same factor for each turn), but from measurements this does not appear to be the case. Any insight on this?
By the way, if the spiral with divergence >1 is NOT a logarithmic spiral, that feature should be added. In a logarithmic spiral the angle between the radius and the tangent line at any point on the spiral is a constant. It can be specified mathematically as r = a*e^(k*theta). (It could probably be more correctly described as an exponential spiral.)
--David Chandler