QUESTION: I would like to use the union module in EVS.  I have a chemistry file with multiple analytes and would like to calculate a volume of a union using the volumetrics module.  I have connected union to explode and scale, added subsetting values for each analyte and then added a volumetrics module. It seems to only show one analyte at a time in the volumetrics module?

You’re close, but you just have a misconception of how things SHOULD work.  The union of multiple analytes is a SPATIAL concept.  It is the volumetric subset of your site where you meet the criteria of A or B or C.

Within that union, you will then still have all analytes at varying concentrations.  Connecting volumetrics after union allows you to compute analyte masses for each analyte ONE-AT-A-TIME within the union subset.  volumetrics connected to union will give you the total soil volume of the union of all analytes.

However, each volumetrics calculation can only do chemical mass computations for one analyte at a time.