2-D Spectral Analysis Results Dialog

While the spectral values are being computed, the 2-D results screen is updated with the new values.

Figure 1: Constant Strength Spectra for Displacement

Constant Strength Displacement Spectra

Figure 2: Constant Ductility Spectra for Normalized Strength

Constant Ductility Displacement Spectra

Data Export

Spectral analysis results can be exported from the program by writing them to a data file. Since the program computes about 11 quantities for each analysis, and performs a number of analyses determined by varying two parameters (period and strength/ductility), the number of results could be very large. And since the user might only be interested in only one quantity, it was chosen to only save the data of the plot. The data can be written out in one of two forms:

General form: where each series in the plot is written out as two columns, for the X and Y values respectively. So if there were Ns series in the plot with Nd number of points each , they would be written as 2Ns columns with Nd rows in each. A first row would be added which carries the value of the series parameter for each series.

Array form: That's when the X-axis is one of the parameters used for the analysis (period for example). In this case, the X values would be shared between all the series, and only one column would be needed for the X values (first column) with N columns for the Y data. Again, a first row is added which holds the parameter that differentiates series.

The user can pick one of the applicable forms in a small dialog that is displaced upon clicking on the "Save Data" button.

2D Controls

The 2D dialog has many controls to customize how the data is plot and how the chart looks. The following outlines those controls.

Plot

Features a "3D Plot" button, which calls the 3-D plotting window, and the "Save Data" button.

Series

1. A "Flip XY" button will exchange the X and Y coordinates.

2. A drop down menu (combo box) allows choosing which variable should be used to connect points into series. This allows the use to use any of the two parameters as the X axis variable, this can be done by selecting the other parameter in the combo box. Simply this allows the data to be viewed in two different ways (for same X and Y quantities). By default, BiSpec will initialize the selection such that the minimum number of series is displayed.

3. A "Show Legend" checkbox can be turned on or off by the user to show or hide the legend containing the values of the series parameter (for each series). This is on by default, except when the number of series exceeds 10; BiSpec would then turn off that option when the window is created.

4. A "Show Symbol" checkbox can be turned on or off by the user to show or hide the data symbols. Data is connected by lines. Turning on this checkbox would add symbols at each point. This option is off by default.

X-Axis

Two radio push buttons provide a selection between a linear or logarithmic x-axis scale.

Y-Axis

Two radio push buttons provide a selection between a linear or logarithmic y-axis scale

Directions

Three checkboxes for: Direction 1, Direction 2 and Resultant (Maximum combination of both directions). Only Direction 1 is available for 1-D analysis. In general, only one of the three selections can be picked. An exception to that is when there is only one series to be plot, in which case, 1 to 3 of these boxes could be checked, and the different directions quantities can be plot on the same chart, one series per direction.

Values

A "Snap" Check box.

Two text boxes display the coordinates corresponding to the current mouse location above the chart. The displayed coordinates depend on whether Snap is on or off. If Snap is off (default), the boxes show the current coordinates. If Snap is on, the coordinates shown are those of the nearest data point to the mouse cursor.

In This Section

2-D Chart Zooming and Control