Tutorial: Create a Ternary Diagram of Three Variables

Estimated time: 2 minutes.

The Ternary program in the Stats menu is used to create a ternary plot for three variables read from the main datasheet. We will use a different sample file than we used in the earlier lessons of this section.

1. Be sure you have accessed the RockWorks Datasheet program tab, and have opened the Samples project folder.
   
2. Open a new sample file:
   1. In the Project Manager program tab (or docked pane), expand the Datasheet File heading if necessary.
   2. Look for the file named Maps_Soil_Properties.RwDat.
   3. Double-click on that file name to open it.
   4. If you are prompted to save changes to the existing datasheet, click No.

   RockWorks will display this file in the main datasheet. This data set contains an ID, symbol, X and Y location coordinates, and elevation for each sample site. It then lists sand, gravel, and clay percentages, Ca and Mg measurements, several geotechnical measurements, and soil colors. For this exercise, we will display the sand/gravel/clay components in the ternary plot.

3. Select the Ternary Diagram option from the Utilities | Stats menu.
   
4. Data Columns: Use these prompts to establish data setup. The name of the currently-selected datasheet column for each required input field is displayed below each prompt. To change a column name for any of the prompts simply click on the small down-arrow and select another column name. The prompts and column names you need to establish are listed here:
   1. Upper Vertex: Set to the column named Sand for the data to be represented in the upper vertex in the diagram.
   2. Left Vertex: Set to the column Gravel for the data to be represented in the lower-left vertex in the diagram.
   3. Right Vertex: Set to the column Clay for the data to be represented in the lower-right vertex in the diagram.
      
5. Diagram Options: Click this tab to set up the diagram.
   1. Vertex Titles: Here you can establish the diagram and axis titles. (These may already be displayed as defaults.)
      1. Upper Vertex: Sand
      2. Left Vertex: Gravel
      3. Right Vertex: Clay
         
   2. Subdivisions: Click on this tab.
      1. Major Subdivisions: Check this.
      2. Minor Subdivisions: Checked.
      3. Intervals: Choose Major = 10% / Minor = 2%
      4. Line styles: Set the Major Subdivisions to thin, black lines. Set the Minor Subdivisions to thin, gray lines.
         
   3. Triangle Perimeter: Check this option.
      
   4. Axis Labeling: Check this option, and click on the tab to choose 20% for the interval.
      
   5. Tick Marks: Check this, and choose 20% for Increments and Internal for the locations.
      
   6. Classification Overlays: Un-check this. These options will plot a pre-defined diagram in the background with your data points and/or contours in the foreground. The currently available templates include Folk's (1954) siliclastic classification system, Schlee's (1973 - after Shepard) siliclastic classification system, Shepard's 1954 siliclastic classification system, and the USDA soil classification system.
      
   7. Symbols: Check this option. Click on the tab to access the settings.
      1. Uniform: Uncheck this.
      2. Column-Based: Check this option.
         • Symbol Column: Click here and choose the "Symbol" column.
         • Dimensions: Choose Uniform, at a size of 3.0.
      3. Circles: Unchecked.
      4. Table-Based: Unchecked.
      5. Images: Unchecked.
         
   8. Symbol Labels: Unchecked
      
   9. Contours
      1. Grid Smoothing can be ignored since you will turn off the contouring.
      2. Colored Intervals: Unchecked
      3. Contour Lines: Unchecked
         In your own work you may want to request line and/or color-filled contours to illustrate point density.
         
6. Other diagram layers:
   1. Other 2D Files: Unchecked.
   2. Peripherals: Checked.
      1. Title: Checked.
         • Primary Title: Type in:  Sand/Gravel/Clay Distribution
         • Secondary Title: Type in:  Site 27B
      2. The other Peripherals options can be unchecked.
         
   3. Border: Unchecked.
      
7. Click Continue to proceed.

   RockWorks will read the values from the Sand, Gravel, and Clay data columns. Each sample will be normalized such that the three components add up to 100%. The symbol for that sample will be plotted at that point in the diagram, with 100% sand represented at the top, 100% gravel represented at the left vertex, and 100% clay at the right vertex.

   In the example below, the single sample contains 60% sand, 30% gravel, and 10% clay.

   

8. Close this window by clicking the Close button (X). Answer No to the save-file prompt.

  Ternary Diagrams

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