Creating Stiff Diagram Maps

RockWorks | Utilities | HydroChem | Stiff Map

This program is used to read a listing of ion concentrations and sample locations from the RockWorks datasheet, create a Stiff diagram for each sample, and create a map that displays each sample's Stiff diagram at the proper map location. The example above shows a portion of a Stiff map combined with a TDS contour map.

Here is a summary of all of the parts of a Stiff diagram. Inclusion of many of the components is determined by settings available in the Stiff Map Options window.

Stiff diagrams plot milli-equivalent concentrations of cations on the left side of the diagram and of anions on the right. Each ion is plotted as a point, and the points are connected to form a polygonal shape. The ions are plotted in a consistent order (Na+K across from Cl; Ca across from HCO3 + CO3; Mg across from SO4) so that each polygon becomes that sample's "signature". Additional ions, if present, are plotted in the order that they are listed, below the standard ions.

Concentrations entered in the source data file in units of milligrams per liter are converted to milli-equivalents per liter for display on the diagram. (See Conversion Factors.)

Menu Options
Step-by-Step Summary


  1. Access the RockWorks Datasheet program tab.
  2. Create a new datasheet and enter/import your hydrochemistry data into the datasheet.
    Or, open one of the sample files and replace that data with your own. See Data Layout for datasheet examples.

    ! Click the Example button at the top of the window to load a sample file that is installed with the program.

  3. Select the Utilities | HydroChem | Stiff Map menu option.
  4. Enter the requested program settings, described above.
  5. Click the Continue button to proceed.

    The program will read the ion concentration information from the datasheet, convert the ppm or mg/l measurements to milli-equivalents per liter based on the conversion factors. For each sample, cations will be represented with points along the left side and anions with points along the right side, scaled horizontally based on their milli-equivalent values and the requested horizontal scaling. Vertical spacing of points will be based on the requested point spacing. Required ions are drawn in a specific order; additional ions are drawn as points below them. The points in each sample will be connected to form a polygonal shape; the polygon will be filled with solid color if requested. The program will then rescale each individual diagram to the dimensions you entered, and will center the diagram on the X,Y map location.

  6. You can adjust any of the diagram options and click the Continue button to regenerate the plot.
  7. View / save / manipulate / print / export the map in the RockPlot2D window.

Tip: Use File | Save to save the Stiff diagram map as an .Rw2D file. Use File | Append to append it to an existing map, such as a contour map.



Back to Hydrochemistry Menu Summary

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