# How to find fractal dimension of Gosper Island

1. Feb 26, 2012

### dracobook

Hi, I'm not sure if this is the right place for this....if it isn't if I could be redirected/if a moderator could move my post to the right place I would greatly appreciate it.

In any case, I am trying to understand fractal dimensions. I read through wikipedia's description and I believe I kind of understand it. I understand how one gets the fraction dimension for Koch snowflake or Sierpinski triangle. However, I cannot figure out the same thing for the Gosper Island. http://www.wolframalpha.com/input/?i=Gosper+Island&a=*C.Gosper+Island-_*Formula.dflt-&f2=2&x=12&y=10&f=GosperIsland.n_2 . It seems to me that it should be N = 7 and epsilon = 1/3 where N and epsilon are discussed here http://en.wikipedia.org/wiki/Fractal_dimension. However apparently Hausdorff dimension gives log(9/7) which suggests to me that N = 9 and epsilon = 1/7, which confuses me greatly.

If someone could help better understand fractal dimensions and what I am missing here I would greatly appreciate it. Thanks in advance!

2. Feb 27, 2012

### xaos

this may be incorrect, but this is how i interpreted the explanations.

at iteration zero start with a side of unit length. it has one cover of diameter length one. N=1, L=1

at iteration one, we have replaced the side with three sides each of length 3/7. equivalently, there are three coverings each of diameter 3/7
N=3, L=3/7

at iteration two, we have nine sides, each now scaled by (3/7)th's of (3/7)th's.
N=3^2, L=(3/7)^2

continuing...
N=3^n, L=(3/7)^n

so using the equation
Dimension = - log(N^n)/log(L^n) = - log(3)/log(3/7) = 1.296?

3. Feb 28, 2012

### Bacle2

Notice that the dimension given in Wolfram is the dimension after only two iterations; after 4 iterations it was 81/49.