In Origin 2021b, we introduced Durov Plot (menu Plot:Specialized:Durov) and Stiff Diagram (menu Plot:Specialized:Stiff). These two graph types are good additions to the existing Piper diagram in Origin for charting the chemistry of a water samples.
Durov Diagram is based on the percentage of major ion milliequivalents in sample waters. The Cations and Anions values are plotted on two separate triangular panels and the data points are projected onto a square grid at the base of each triangle. In addition, Durov Diagram allows to directly compare two other groundwater parameters, pH and the total dissolved solids (TDS).
Stiff diagram is useful in the analysis of groundwater ion concentration. It plots 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.
Stiff diagram in Origin has the following controls:
- The ions on the polygon can be grouped or reordered based on its group information saved in worksheet column header.
- User can specify add additional cation/anion to the graph and the grouping and order of these ions can also be controlled.
- Origin also has Stiff Map plot type that allows to position each sample based on its XY coordinates.
In Origin 2021b, You can choose Help: Learning Center… On Graph Samples tab, enter keyword 2021b to find these graph samples with associated data.