You can create a Wilcox diagram in Grapher using the attached template and the following steps:

1. Download the attached WilcoxDiagram.grf and Axes.dat files. Make sure to save the two files to the same directory.
2. Click File | Open, select the GRF file, and click Open.
3. In the Grapher dialog warning you Unable to open worksheet file, click Yes.
4. In the Open Worksheet Linked to ... dialog
   1. Select your data file.
      The data should be formatted in three columns with a header row where Column 1 is the Conductivity data, Column 2 is the SAR data, and Column 3 is the Class data. If you have no Class data, copy one of the other two columns into Column 3. See the attached data.txt for an example data set, if needed.
   2. Check the box next to Use this worksheet for remaining items at the bottom of the dialog.
   3. Click Open and the plot is created. 
5. To change the class scatter plot symbols,
   1. Select Class Scatter Plot in the Object Manager.
   2. Click the Edit button next to Classes on the Plot page in the Property Manager.
   3. If your classes are not called 1, 2, 3, 4, and 5, change the Method to Custom and then back to Name to reset the class names from your own class column.
   4. Edit the classes as desired. See the article Change the Symbol Shape and Color for a Class Plot in Grapher for more information about editing classes in Grapher.

Below are some customization options for this particular plot using this template:

• To turn on the category labels on the X axis and turn off the colored category bar, check the box in the Object Manager next to C1, C2, C3, C4 Labels (Bottom) and then uncheck the box next to Horizontal Categories.
• To turn on the category labels on the Y axis and turn off the colored category bar, check the box in the Object Manager next to S1, S2, S3, S4 Labels (Right) and then uncheck the box next to Vertical Categories.

Contact us if you would like to add your vote to our suggestion file for a built-in Wilcox diagram.

Updated July 25, 2019