In Grapher 13, true classed Piper plots and unclassed Piper plots were added as inbuilt graph types, so plotting your data is easier than ever! You can follow the steps in this article to create Piper plots in Grapher 13: Can Grapher Create A Piper Plot? If So, How?
A sample Piper plot created in Grapher 12.
A sample plot and data file are attached (G12 - PiperPlot.zip). A second sample file uses colored symbols as labels is also attached (G12 - PiperColor.zip). In addition, a Piper plot sample is contained in the Samples directory for Grapher 12.
Both data files displays ID, cations, anions, and two combined columns. The anions in columns E, F, and G (highlighted in blue below) should be normalized to add up to 100%. The cations in column B, C, and D (highlighted in red below) should be normalized to add up to 100%. After the columns are normalized the worksheet can be used to create the Piper plot. Columns I and J (highlighted in green below) use a formula to create combined data. The Piper for grapher colors.xlsx file contains color names and a symbol in column K. Columns L and M are used to label the cation bottom left ternary diagram.
Verify that the cations and anions add to 100 before creating the Piper plot.
Grapher 11 - Creating classed piper plots
Using different symbols in a Piper plot is typical to show different collection areas or to demonstrate differences in total dissolved solids amongst the samples.
In previous versions of Grapher, in order to create a Piper plot you had to use a combination of ternary diagrams, so to modify your symbols you had to add a symbol column to your data file and go through a workaround to display these custom symbols. Grapher 11 introduced a classed ternary diagram, so it’s easier than ever to create your Piper plot with symbol classes! To do so:
- Download the attached zip file containing the template files (G11 - PiperPlot.zip).
- Unzip the file to extract the GRF Grapher file and the XLSX data file. The data file displays class name, cations, anions, and two combined columns. The cations and anions should all be normalized to add up to 100%. Additionally there are three extra columns at the end of the file for custom axes labels.
- Open Grapher 11. In the Welcome dialog click Open Document.
- In the Open dialog, navigate to the XLSX data file, select it, and click Open. The data file opens in Grapher’s worksheet.
- Replace data in Cols B-G with your own normalized cation and anion concentrations.
- Go to Cells | Data | Transform. Change First row to 2 and then type Transform equation: I=G+F. Click OK.
The Transform dialog showing the transform used to calculate the x component for the diamond plot.
- Go to Cells | Data | Transform. Change First row to 2 and then type Transform equation: J=B-sin(D2R(30))*I. Click OK.
The Transform dialog showing the transform used to calculate the y component for the diamond plot.
Note that the D2R here is important because it converts the 30 (degrees) to radians.
- Use File | Save to save the data file to the same name, or File | Save As to save to your own name.
- Click File | Open.
- In the Open dialog navigate to the GRF file that came in the ZIP file you downloaded in step 1. Select it and click Open.
- If you saved your data to a new name, click on Class Scatter Plot 1 under Piper Points in the Object Manager.
- In the Plot tab of the Property Manager, change the Worksheet to your new data file.
- Repeat steps 11 and 12 for Ternary Class Plot 1 under Right Class Ternary and Left Class Ternary.
Now you have a Piper plot of your own data using custom symbol classes. In just a few short minutes you’ve plotted a visually-appealing, completely customizable Piper plot which will wow your audience and quickly inform them of what the groundwater has to offer.
Updated September 21, 2018