Piper Diagrams are produced through ESdat using a modification of an Excel based Piper Diagram developed by the USGS.  The original USGS copy was downloaded from http://nevada.usgs.gov/tech/excelforhydrology/WaterQualityTools/PiperPlot-QW.XLS.

Geochemistry charts, including Piper Diagrams are available under the graphing button when looking at the milli-equivalents water chemistry output.  Outputs in mill-equivalents are available for compounds where the equivalent weight is specified in the Chemistry Lookup Table.

It is essential that chemistry data be given the correct ChemCode for the data to be identified and output to the Piper Diagram.  The relevant codes are:

During output the data can be grouped by a specified output field, such as Monitoring Unit or Area.  Upon production of the Piper Diagram you can change the chart settings.  Chart settings include the colours used for displaying the points and the position of the legend.