Automeris is a great option for those uninterested in programming: https://automeris.io/.
However, it has limitations — an account is required, it cannot generate a set number of points (meaning it requires manual configuration by adding / removing points), and it cannot generate symmetrical plots; and once the X and Y values are generated.
Despite this, it is a good tool!
Start by creating an account. Then navigate to the “Load Image” button on the sidebar and import the chosen image. A pop-up will appear - as the goal is to make a 2D scatter plot, we want to use “2D (X-Y) Plot”
The axis must be set up in a specific order:
- X1 (the point furthest to the left)
- X2 (the point furthest to the right)
- Y1 (the lowest point)
- Y2 (the highest point)
Once these are set, a pop-up will appear asking to confirm the coordinates. Double check and confirm!
Next, to generate the points for tableau, move to the section on the right side panel called “Automatic Extraction”
First, change the “Foreground Color” to the primary color of the shape (in my case, black)
Then, under “Algorithm” edit the Delta X and Delta Y - smaller numbers will give more points, while using larger numbers will give less.
On the left hand side, the number of data points that result from your Delta X and Y configurations is available. The goal is for this number to be as close as possible to the number of data points in the data set.
Here is where Automeris shows its weaknesses: there is a lot of fiddling with the Delta X and Ys to get the ‘correct’ number of points, and there is very little control on how the end points look. There is no symmetry! No grid!
My future data set also has 144 items - it is a challenge to get it this low and have a good looking shape.
To export these points, click the “View Data” button on the left hand side.
Then Download the data as a CSV and append your data to the points using excel or google docs, copy + pasting the rows of one onto the other.
If you have a mismatch between the number of points you have generated and the number of data points you have, then part of the image will be cut off.