GMS:Datasets

A data set is a set of values associated with each node, cell, vertex, or scatter point in an object. A data set can be steady state (one value per item) or transient (one value per item per time step). The values in the data set can be scalar values or vector values. Certain types of objects in GMS have an associated list of scalar data sets and a list of vector data sets. Each of the following objects in GMS can have both scalar a vector data sets:

• TINs

• 2D Meshes

• 2D Grids

• 3D Meshes

• 3D Grids

The following objects can only have scalar data sets:

• Borehole Sample Data

• 2D Scatter Point Sets

• 3D Scatter Point Set

The commands for manipulating data sets are located in the Data menu.

Data sets are used for both pre- and post-processing of models. For example, a scalar data set associated with a 3D grid can represent starting values of head or values of hydraulic conductivity for a groundwater modeling problem. Another data set associated with the same grid may represent computed head values. Data sets can be used to generate contours, iso-surfaces, vector plots, and animation sequences.

Generating Data Sets

Data sets can be generated in a variety of ways. They can represent output from a groundwater model (head, drawdown, etc.). They can represent tabular values in a text file entered by the user or exported from another application such as a GIS. They can be created by interpolating from a scatter point set to a TIN, grid, or mesh. Data sets can also be generated by performing mathematical operations on other data sets with the Data Calculator.

One advantage of the data set list approach for managing information is that it facilitates transfer of information between different types of models or models with differing resolution. This is accomplished through scatter point sets and interpolation. TINs, borehole contacts, borehole sample data, grids, and meshes can all be converted to a 2D or 3D scatter point set. When an object is converted to a scatter point set, all scalar data sets associated with the object are copied to the new scatter point set. The data sets can then be transferred from the scatter point set group to other objects of any type using one of the supported interpolation schemes.

Importing/Exporting Data Sets A data set can be exported by right-clicking on the data set in the Project Explorer and select the Export command. The Save As dialog has three filter types that can be exported:

• Binary Data Set Files (*.dat)

• ASCII Data Set Files (*.dat)

• HDF5 data Set Files (*.h5)

A data set can be imported by right-clicking on any of the objects explained above in the Project Explorer and select the Import Data Set command. This command brings up the File Open dialog.

Project Explorer

Data sets are displayed and managed in the Project Explorer. Click here to learn about data sets in the Project Explorer.

Active Data Set

Each object (TIN, Grid, Mesh, or Scatter Point Set) in GMS has a set of values which is designated as the "active data set." The active data set is an important part of model visualization in GMS. Each time the display is refreshed, the contours and other display features are generated using the active data set.

The active data set and time step are displayed in the Project Explorer. Left-clicking on a solution or data set in the Project Explorer makes that item "active" and the display is automatically updated in the GMS window. The table below shows the icons displayed next to the active data sets.

File:Tree DataSetActive.gif	active scalar data set
File:Tree VectorDataSetActive.gif	active vector data set
File:Tree CCFDataSetActive.gif	active ccf data set

Data Set Info

Selecting the Properties command in right click menu on a data set in the Project Explorer will bring up the Data Set Info Dialog. The components of the dialog are as follows:

Statistics

A set of statistics related to the active data set is displayed on the left side of the Data Set Info dialog. the statixtics for all time steps can be shown by selecting the Show all time step stats. toggle. A histogram of the data values is displayed on the right side. Right-clicking on the plot and selecting the Plot Data command brings up the X-Axis Precision dialog. This dialog enables users to set the precision of the x-axis of the Histogram.

View/Edit Values

For data sets associated with model solutions, the data values can be displayed in a spreadsheet using the View Values button. For all other data sets, the button label changes to Edit Values and the spreadsheet can be used to change the data set values.

Active/Inactive Flags

If the currently selected module is the 3D Grid module, the active/inactive status of cells can be changed by selecting the Edit button at the bottom left of the dialog. This brings up the Active/Inactive Flags dialog.

Date/Time Display

For a transient data set, the time values can be displayed in the Time Step Window using either a relative time format (e.g., 100.0) or using a date/time format (e.g., 1/12/1998 3:23:48). The relative times are computed using a reference time that is defined for the model (MODFLOW, FEMWATER etc.). The reference time represents the date/time corresponding to t=0.

Data Sets in the Project Explorer

The solutions and data sets associated with a particular object (grid, mesh, scatter point set, etc.) are managed using the Project Explorer.

Data Sets

File:Tree DataSet.gif	scalar data set	File:Tree DataSetActive.gif	active scalar data set
File:Tree VectorDataSet.gif	vector data set	File:Tree VectorDataSetActive.gif	active vector data set
File:Tree CCFDataSet.gif	ccf data set	File:Tree CCFDataSetActive.gif	active ccf data set

3 different types of data sets are shown in the Data Tree: scalar, vector, and cff. The icons used to identify the data sets are shown below.

If the active data set is transient then the time steps are displayed in the Time Step Window.

Solutions

Solutions are output from a numerical model that GMS supports. Solutions are shown in the Project Explorer as a folder with an lock on it File:Tree Folder Lock.gif. If a solution is transient then the time steps are displayed in the Times Step Window. Data sets can not be moved into or out of a solution folder. Also, the solution may contain text files such as the *.out and *.glo files produced by MODFLOW. These files can viewed by right clicking on the item and selecting View File from the pop up menu, or you can double click on the item.

Clicking on a solution or data set makes that item "active" and the display is automatically updated in the GMS window.

Folder

The data sets and solutions are organized by folders. The user can create new folders and move data sets, solutions, and folders to other folders anywhere on the Project Explorer. Folders can be created by right clicking on the certain items in the Project Explorer and selecting New Folder in the menu. A data set or folder can be deleted simply by selecting the folder and selecting the Delete key or by right-clicking on the item and selecting the Delete option in the corresponding pop-up menu. Statistics about a data set can be viewed by right-clicking on a data set and selecting the Properties option from the pop-up menu.