#TweakThursday 26: Creating Fibonacci Spiral

Happy New Year 2017!

Recently I have been interested in charting mathematical functions, such as Sigmoid and Trochoids. Sigmoid has found applications in Bump and Sankey charts. For other math functions, it is just a great exercise to visualize them and to learn creating beautiful curves using Tableau.

So, I found this Fibonacci chart below by Zen Master Noah Salvaterra who was a math professor. He has done some dazzling work in visualizing 3D objects and some pretty sophisticated math functions.

Note that Fibonacci Spiral is only an approximation to the Golden Spiral.

In this Fibonacci spiral chart, he drew it using straight lines between spiral points.

So I tweaked over the holidays to draw it more like a real spiral. Certainly I used data densification to create interpolations between the spiral points. Click the image to go to the interactive version.

First we have to create an index for the interpolating points between the spiral points. [Point_Base] is used to create bins and index with data densification.

The key calculations of the coordinates of the interpolation are as follows:

With the above x_spiral_axis and y_spiral_axis, I am able to draw the spiral as above.

Voila, have a great 2017!