RockWorks | Utilities | HydroChem | Stiff Diagram
This program is used to read a listing of ion concentrations from the datasheet and create a Stiff diagram for groundwater ion concentration analysis.
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 Diagram 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
Menu Options
- Input Columns: The prompts along the left side of the window tell RockWorks which columns in the input datasheet contain what data.
Click on an existing name to select a different name from the drop-down list.
- Sample ID: If you have sample numbers listed for your sites, choose the column where these are listed. These will display inside or outside the Stiff polygons.
- Symbol: Choose the column that lists specific symbols for the individual samples.
- Na, K, Ca, Mg: Choose the columns that list these required cations. The measurements must be listed in ppm or mg/l units.
- Cl, HCO3, CO3, SO4: Choose the columns that list these required anions. The measurements must be listed in ppm or mg/l units.
- Cation A, B, C, D: If you are including any additional cations (see Additional Cations, below), choose their columns here.
- Anion A, B, C, D: If you are including any additional anions (see Additional Anions, below), choose their columns here.
- Titles: Expand this item to specify text, if any, for the main and secondary diagram titles. You may enter up to 60 characters for each title. Expand these items to select their color.
- Additional Cations: In the middle pane of the program window, expand this heading to turn on up to 4 additional (non-standard) cations to be included in the Stiff diagram polygons. Click in each check-box to turn an ion on or off. Be sure that the ions are correctly identified in the input columns to the left.
- Conversion Factors: For each additional ion, you also need to declare a conversion factor to convert from ppm or mg/l to milli-equivalents. See Conversion Factors for help.
! This is important - RockWorks will not know this conversion factor automatically. You need to enter it manually.
- Additional Anions: Expand this heading to turn on up to 4 additional, non-standard, anions to be included in the Stiff diagram polygons. Click in each check-box to turn an ion on or off. Be sure that the ions are correctly identified in the input columns to the left.
- Conversion Factors: For each additional ion, you also need to declare a conversion factor to convert from ppm or mg/l to milli-equivalents. See Conversion Factors for help.
! This is important - RockWorks will not know this conversion factor automatically. You need to enter it manually.
- Scaling
- Horizontal: This determines how the diagram will be scaled from left to right. The labeling interval along the horizontal axis is established below, under Diagram Options / Horizontal Axis.
- Select Automatic to have the program determine the range of the horizontal scale bar automatically, based on the maximum ion concentration on each page. If you check Equal Scales, then the program will dimension the left and right sides to equal ranges.
- Automatic scaling is handy for the first runs with a data set, and if your data is pretty consistent throughout.
- Or select Manual to set the scale bar range to the milli-equivalents/liter values that you enter in the prompt boxes.
- Manual scaling is handy if you don't want different pages of a data set to be shown at different scales.
- Vertical Point Spacing determines how far apart the sample points are plotted and how stretched the Stiff polygons will appear. Note that samples with more ions will be generate longer polygons than those with fewer ions, even if the point spacing is constant.
- Text and Point Scaler: Use this setting (default = 1) to increase or decrease all text and vertex point sizes universally. Use Polygons per page .
- Diagram Options: Expand this item to choose diagram components and colors.
| Column titles: Check this item to plot titles above the horizontal axis and expand this item to enter the title text and color. |
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| Horizontal Axis: Check this item to plot a horizontal axis line with tick marks and labels. Expand this item to set the tick & label increments and color. The appropriate increment to enter will depend on the concentration ranges of your data. See Scaling, above, to establish the range of the horizontal scale bar. |
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| Vertical Axis: If activated, the program will draw a line of the specified color in the midline of the diagram. |
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| Vertex Points: If there is a check in this box, the program will include solid circle points at each vertex of the Stiff polygons. The program will not use the symbols stored in the main datasheet. Expand this item to select the point color. The size of the symbols is controlled by the Text and Point Scaler setting, described above. |
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| Vertex Labels: If activated, the vertex points will be labeled with the ion represented there. Select the color by expanding this item. |
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| Sample Names: If you want each polygon to be labeled with the sample number, insert a check in this box. Expand this item to select label color and whether the label is to be plotted inside or outside the polygon. Note that if you selected centered positioning and have Fill Polygons checked (below), you will need to be sure that the text color is set dark enough to be visible. |
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| Fill Polygons: Insert a check here if you want the polygons to be filled with solid color rather than drawn as outlines. The colors used are those specified for the Symbols in the main datasheet. |
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| Border: Insert a check here to surround each diagram by a solid line border. Leave this box unchecked if the diagram should not include a border. |
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- Polygons per Page: Enter here the number of polygons that are to be plotted on each page. The program will create a separate plot window for each page of polygons.
Note that if you are creating multiple pages and if you've selected Automatic scaling for the horizontal axes, each page may represent different scaling.
- Multipage Warning: Insert a check here if, prior to creating a Stiff diagram, the program is to display a message box warning you that more than one page of polygons is going to be created. The number of pages that will be created depends on the number of samples in the datasheet, the number of polygons you have requested per page, and the point spacing.
Step-by-Step Summary
- Access the RockWorks Utilities program tab.
- 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. (In the Samples folder, an example file = "\RockWorks17 Data\ Samples\Hydrochemistry_01.rwDat".)
- Select the HydroChem | Stiff Diagram menu option.
- Enter the requested menu items, described above.
- Click the Process button to continue.
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.
Multiple pages may be required if there are more samples in the datasheet than have been established as the Polygons per Page setting. The program will display a multiple-page notice if you have requested this; you may cancel the plotting process if you wish.
- You can adjust any of the diagram options along the left and click the Process button to regenerate the plot.
! Each time you click the Process button, the existing display will be replaced.
- View / save / manipulate / print / export the diagram in the RockPlot2D window.
Back to Hydrochemistry Menu Summary
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