Data sets are managed through the Data Sets dialog box. To display the Data Sets dialog box, select Data|Edit Data Sets…
Data sets have a three-dimensional array of values, which correspond either to elements or to nodes in the grid. (These values correspond to “properties” as used in section 4.2.1.3 of the PHAST manual (Parkhurst and others, 2004). In this report, “properties” do not refer to spatially distributed data.) This section describes each of the properties of a data set that the user can change.
All of the data sets required by PHAST are displayed in the Data Sets dialog box along with data sets that the user has created. If a data set is sometimes required by PHAST but is not being used in the current project, it is displayed in the dialog box in italics and with a light gray background. Each data set has several properties: its name, whether or not it is visible, type, orientation (top, front, side, or 3D), where it is evaluated (nodes or elements), its units, its formula, and for 2D data sets, its interpolation method. For data sets used directly by PHAST (Table 3), the name, type, orientation, and where it is evaluated can not be changed. For data sets created by the user, these can be changed. For some data sets that are used directly by PHAST, the user can use a special PHAST-style interpolation method (p. 23).
To create a new data set, click the Add or Insert button in the Data Sets dialog box. Clicking the Add button, adds a new data set at the end of the table. Clicking the Insert button, inserts a new data set above the currently selected row in the table. To delete a data set, select the row in the table containing the data set and then click on the Delete button. (Users can not delete data sets that are used directly by PHAST.)
The Name of a data set is used to identify it in formulas for other data sets and when exporting the corresponding PHAST data set (if there is one). A name must begin with either the underscore character or one of the letters A through Z in either upper or lower case characters. Subsequent characters must be the underscore character, the letters A through Z in either upper or lower case characters or the digits 0 through 9. Spaces are not allowed in the names of data sets. Data Set names are case insensitive. Thus, “A_NAME”, “a_name”, and “A_Name” are all equivalent.
If a data set is Visible, it will appear on the
"Data Sets" tab of the Object Properties dialog box (p. 49).
Otherwise it will not appear there.
Each data set must have a Type that indicates what kind of data is stored in it. Valid types are "Real", "Integer", "Boolean", and "Text”. These types represent real numbers, integers, true/false values, and text respectively. Most of the data sets built into GoPhast are "Real" or "Integer". The "Active" data set is "True/False". No built-in data sets are "Text".
The Orientation of a data set determines the shape of a data set. The possible choices are 2D Top, 2D Front, 2D Side, and 3D. Most data sets have an "Orientation" of "3D". A data set with a 2D Top orientation has a single layer but multiple columns and rows. A data set with a 2D Front orientation has a single row but multiple columns and layers. A data set with a 2D Side orientation has a single column but multiple rows and layers. A data set with a 3D orientation has multiple columns, rows, and layers.
If Evaluated At (the evaluation location) is set to "Elements" then the values in the data set correspond to elements in the model grid and are evaluated at the centers of elements. If "Evaluated At" is set to "Nodes" then the values in the data set correspond to nodes in the model grid. For orientations of "2D Top", the data set values correspond to the elements or nodes in the first (bottom) layer of the model grid. Similarly for "2D Front" and "2D Side" the data set values correspond to the elements or nodes in the first row or column respectively of the model grid.
The Units of a data set are meant to serve as a reminder to the user. The units do not affect how values are computed.
The Default Formula of a data set is a mathematical expression that defines the value that will be applied to each location in a data set unless a value for that location is specified in some other way (such as being set by objects). A formula may be a simple numerical value or it can express much more complex relationships. See the section on Formulas for more information. (See p. 25.)
If a data set is a two-dimensional data set, it can use one of the 2D Interpolation methods in conjunction with one or more objects to define the values of a data set. If an interpolation method is being used with a data set, controls related to that interpolation method become enabled in the bottom part of the dialog box when the data set is selected. Three interpolation algorithms are available in GoPhast: Nearest, Inv. Dist. Sq. (Inverse Distance Squared), and Nearest Point. See the section on “Interpolation Methods” for more information. (See p. 22.)
If the data set is one of the PHAST data sets with which PHAST-style interpolation can be used, the "Use PHAST interpolation for all cells" check box will be enabled when the data set is selected. It the user checks this check box, the other controls related to PHAST-style interpolation will become enabled. See “PHAST-Style Interpolation” on p. 23.
In a new GoPhast project, the only data sets present are those required by PHAST (Table 3). However, the user can create additional data sets for his or her own purposes. One reason to create a data set would be to use it in a formula for one of the data sets required by PHAST. For example, the user could create a 2D data set that represented the hydraulic conductivity of a particular geologic unit. It could then be used to assign Kx for just those elements that were part of that geologic unit.
Table 3. Data Sets Required by PHASTData Set |
Description |
PHAST equivalent |
---|---|---|
Active |
Specifies whether an element in
PHAST is active or not. |
MEDIA, active |
Kx |
Specifies the hydraulic
conductivity in the X direction. |
MEDIA, Kx |
Ky |
Specifies the hydraulic
conductivity in the Y direction. |
MEDIA, Ky |
Kz |
Specifies the hydraulic
conductivity in the Z direction. |
MEDIA, Kz |
Porosity |
Specifies the porosity. |
MEDIA, porosity |
Specific_Storage |
Specifies the specific storage. |
MEDIA, specific_storage |
Longitudinal_Dispersivity |
Specifies the longitudinal
dispersivity. |
MEDIA, longitudinal_dispersivity |
Horizontal_Transverse_Dispersivity |
Specifies the horizontal
transverse dispersivity. |
MEDIA, horizontal_dispersivity |
Vertical_Transverse_Dispersivity |
Specifies the vertical
transverse dispersivity. |
MEDIA, vertical_dispersivity |
Initial_Head |
Specifies the initial head. |
HEAD_IC, head |
Initial_Water_Table |
Specifies the initial water
table. |
HEAD_IC, water_table |
Chemistry_Initial_Solution |
Specifies the initial solution. |
CHEMISTRY_IC, solution |
Chemistry_Initial_Equilibrium_Phases |
Specifies the initial
equilibrium phases. |
CHEMISTRY_IC, equilibrium_phases |
Chemistry_Initial_Surface |
Specifies the initial surface
properties. |
CHEMISTRY_IC, surface |
Chemistry_Initial_Exchange |
Specifies the initial exchange
properties. |
CHEMISTRY_IC, exchange |
Chemistry_Initial_Gas_Phase |
Specifies the initial gas phase
properties. |
CHEMISTRY_IC, gas_phase |
Chemistry_Initial_Solid_Solutions |
Specifies the initial
solid-solution properties. |
CHEMISTRY_IC, solid_solution |
Chemistry_Initial_Kinetics |
Specifies the initial kinetic
properties. |
CHEMISTRY_IC, kinetics |
Print_Chemistry |
Specifies the "Print Chemistry"
distribution. |
PRINT_LOCATIONS, chemistry |
Print_XYZ_Chemistry |
Specifies the "Print XYZ
Chemistry" distribution. |
PRINT_LOCATIONS, xyz_chemistry |