An important feature of SMS is that the interface to each of the separate modules is designed in a consistent fashion. Once the user becomes familiar with the interface to one of the modules, the other modules can be used with little additional training. In order to help provide a consistent interface, the concept of generic functional data sets is used in SMS.
A data set consists of a scalar or vector value for each node in a mesh, each vertex in a scattered data set, or each cell in a grid. A data set can be either steady-state (constant - one value per item) or dynamic (transient - one value per item per time step). Dynamic data sets are represented using data sets for different points in time. Meshes, grids, and scatter point sets have independent lists of data sets.
A data set of scalar values, or scalar data set, is used to represent quantities such as the water surface elevation or depth computed by a hydrodynamic model or empirical values used as initial conditions for input to a dynamic model. A data set of vector values, or vector data set, is used to represent quantities such as flow velocities or stresses. The commands for manipulating data sets are located in the Data menu. The Data menu is available in each of the modules, but varies in its contents. Refer to the help for a specific module to see data commands for that module.
Data sets are used for both pre- and post-processing of models. For example, a scalar data set associated with a two dimensional mesh can represent starting or initial values of water surface elevation. Another data set associated with the same mesh may represent initial velocity values. SMS can export these values as an initial condition file for FESWMS and HIVEL2D. All data sets can be used to generate contours, color fringes, vector plots, animation sequences and other data sets. Data sets can be imported from a file, created by interpolating from a scatter point set, or computed using other data sets, constants and mathematical operators.
Another example of the use of data sets is to compare the difference in the solutions from two separate simulations on the same finite element mesh. The two solutions can be read as data sets and the Data Set Calculator can be used to compute the absolute value of the difference between the two data sets. The resulting data set can be contoured just like any other data set.
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 sets of scatter data points and interpolation. Meshes and grids can be converted to 2D scatter point sets. When an object is converted to a scatter point set, all data sets associated with the object are copied to the new scatter point set. The data sets can then be interpolated from the scatter point set to other objects of any type using one of the supported interpolation schemes.
Data sets are manipulated through the Project Explorer. In addition, new data sets can be computed from existing data sets and/or scalar values using the Data Calculator.
One data set is always highlighted in both the scalar and vector data set lists, shown in both the Data Browser and the Edit Window. If a dynamic data set is highlighted, the time steps for the data set are listed in the Time Steps text box . One of the time steps is highlighted. The highlighted sets are the active data sets for the object. The values corresponding to the active data sets and time steps are used whenever contour, color fringe, and vector plots are generated. In addition, the entire range of time steps of the active data set is used whenever animation film loops are generated.
Whenever a new mesh or grid object is created or read from a file, a scalar data set is created containing the bathymetry, or node bottom elevations for the object. Thus, there is always at least one data set associated with a mesh or grid. It is labeled as mapped in the Project Explorer. Any function may be assigned to be this elevation function using the Map Elevation menu command. SMS treats the currently mapped function differently than other functions in three ways. First, the mapped function value is stored as the "z" component of nodes and is displayed as the "z" value in the edit window. Therefore, the user may edit these values. Second, the mapped function cannot be deleted. Third, for models that support disabled elements, such as FESWMS or RMA2, SMS ignores all functions except the mapped function when fringes or contours are computed and displayed.
There are several other situations in which SMS will automatically create data sets. These include FESWMS Ceiling values, SED2D-WES bed property sets and RMA10 layer data sets.
Data sets can be deleted only through the Project Explorer.
Related
Topics
Contours
Color Ramps
Animations
Vector Visualization