The user can view the output directly from the Peaks Over Threshold editor (tabular and graphical output) or by using the buttons at the bottom of the editor.

Tabular Output

Once the computations for the flow frequency analysis are completed, the user can view tabular output by opening the Tabular Results tab. When this tab is pressed, the results will be displayed as shown in the figure below.

Output on the results tab consists of three tables: Frequency Curves, Distribution Parameters, and Diagnostic Data for Selected Threshold. The Frequency Curve output table contains the percent chance exceedance ordinates, the computed annualized frequency curve quantiles, the expected probability adjusted frequency curve quantiles, and the computed confidence limits (0.05 and 0.95, by default). Data in the frequency curve table can be sorted in either ascending or descending order by clicking in the column header (two mouse clicks are required the first time). The percent chance exceedance ordinates and frequency curves will sort so that the lowest values are on top or the highest values are on top.

The Distribution Parameters table contains the Generalized Pareto distribution location, scale, and shape parameters. If Analytical: Madesen et al. (1997) annualization was selected, this table also contains the Generalized Extreme Value distribution location, scale, and shape parameters.

The Diagnostic Data for Selected Threshold table displays the diagnostic data for the user-selected threshold: number of years of data, number of events in the partial duration series, rate of events, mean excess, and Anderson-Darling right tail weighted test statistics. 

Graphical Output

Graphical output of the frequency curves can be obtained by pressing the Plot Curve button. When the Plot Curve button is pressed, a frequency curve plot will appear in a separate window as shown below. The user can modify the plot properties by selecting the Edit | Plot Properties menu option. A plot properties window will open that lets the user change the line style for each data type, change the axis labels, modify the plot title, and edit other plot properties. The user can also edit line styles by placing the mouse on top of the line or data point in the plot or legend and clicking the right mouse button. Then select the Edit Properties menu option in the shortcut menu. Both the Y and X-axis properties can be edited by placing the mouse on top of axis and clicking the right mouse button. Then select the Edit Properties menu option in the shortcut menu. For example, the user can turn on minor tic marks for the y-axis and modify the minimum and maximum scale for the x-axis.

The data contained within the plot can also be tabulated by selecting Tabulate from the File menu. When this option is selected, a separate window will appear with the data tabulated.  The Edit menu on the graphic window contains several options for customizing the graphic. These options include Plot Properties, Configure Plot Layout, Default Line Styles, and Default Plot Properties. Also, a shortcut menu will appear with further customizing options when the user right-clicks on a line on the graph or the legend.

The code used in developing the plots in HEC-SSP is the same as that which is used for developing graphics in HEC-DSSVue and several other HEC applications. Please refer to the HEC-DSSVue Documentation for details on customizing plots.

Viewing the Report File

A report file is created when the Peaks Over Threshold Analysis computations are performed. The report file lists the input data, user settings, intermediate results (such as partial duration space probabilities and event counts by year), and the results. This file is often useful for understanding how the software arrived at the output. 
Press the View Report button at the bottom of the Peaks Over Threshold Analysis editor to view the report file. When this button is pressed, a window will appear containing the report as shown below.

The computations that were used to create the output are contained within the Report output. Additionally, the Peaks Over Threshold report can be opened using the Results | Report option in the Results dropdown menu at the top of the SSP window.