union

(This module is available only in MVS)

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General Module Function

union is a powerful module that allows for a large number of complex serial and parallel subsetting operations required to compute and visualize the union of multiple analytes and threshold levels. The functionality of the union module can be obtained by creating a network fragment composed of only plume_volume modules. However as the number of analytes in the union increases, the number of plume_volume modules increases very dramatically. The table below lists the number of plume_volume modules required for several cases:

Number of Analytes	Number of plume_volume Modules
2	3
3	6
4	10
5	15
6	21
7	28
n	(n * (n+1)) / 2

From the above table, it should be evident that as the number of analytes in the union increases, the computation time will increase dramatically. Even though union appears to be a single module, internally it grows more complex as the number of analytes increases.

The union of multiple analytes and threshold levels can be equated to the answer to the following question (example assumes three analytes A, B & C with respective isolevels of a, b and c):

"What is the volume within my model where A is above a, OR B is above b, OR C is above c?"

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The figure above is a Boolean representation of 3 analyte plumes (A, B & C). The union of all three is the entire colored portion of the figure. Think of the image boundaries as the complete extents of your models (grid). The "A" plume is the circle colored cyan and includes the green, black and blue areas. The union of just A & C would be all colored regions EXCEPT the magenta portion of B.

Module Input Ports

union has one input port that accepts unstructured mesh data.

Module Output Ports

union has two output ports. The first output port (closest to the left) outputs a new unstructured mesh which contains a merged field containing the union of all analytes with the selected data components available for coloring or subsequent subsetting operations.

The second port outputs a rendered geometry directly to the Viewer.

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Module Control Panel

The control panel for union is shown in the figure above. union's user interfaces changes automatically depending on the selected Analytes in Union to be performed. The Top Panel allows you to select the following parameters:

Turning off the Run toggle allows you to make multiple changes without the module running automatically.

Map Components determines which model data components will be sent to the output ports. The first map component selected will be used to color the output. For example, choosing iso component concentration and map component uncertainty will create a volumetric subset of concentration colored by uncertainty.

The Remove Normals Generation toggle is equivalent to setting Normals Generation (in Object.Modes) to None. This changes the rendering of surfaces and is sometimes preferable.

The remaining panels will be named Analyte 1:, Analyte 2: and so on. Each of these is identical in their options having the following parameters:

Iso Component refers to the model data component used to create the subset. When an iso component is selected, the min and max values of the variable are displayed in the right side of the panel.

The Data Above(on) or Below(off) Iso Level check box (Above Box) is used to display data above the iso level or below the iso level. For example, to display a volumetric subset of all concentrations greater than or equal to 1 ppm, set iso level to 1 (assuming concentration units are in ppm) and set the Above Box to on (check in the box). To see the union of 1 ppm and below, simply turn the Above Box off (no check in box).

The Exponentiated Values toggle makes another type-in field visible which convert real units to logarithmic units for you automatically.

The Iso Level type-in is used to set the level for subsetting the input field. If a value is chosen larger than the max value, the max value is placed in the edit box. Similarly, if a value less then the minimum is input, the minimum value is placed in the box. The default iso level value is the arithmetic average of the minimum and maximum values in the iso component. If your input data has been kriged with log processing, the values here will be the Log of your input data.