Selection
The "Selection" window is divided into four sections: "General data windows", "Automatic selection", "Manual selection" and "Filter".
In this section are identified windows that are used in the analysis process from the traces imported in the previous phase. The section of the graphics within this window takes two configurations which are explained later in this manual page.
General data windows
Window size [s]
In this box is entered the temporal dimension of the windows in which are divided the traces of the recording, following the procedure in the section that describes the analysis process in this guide. As shown in the SESAME project, its value must be at least 20 seconds.
Overlap
In this box is entered the value of the percentage of overlap allowed between the time windows in which the traces of the recording are divided, according to the procedure in the section that describes the analysis process in this guide.
Automatic selection
The selection of the windows can be done automatically by Easy HVSR through the instructions contained in this section.
In practice are set two values: one for the "Initial time" and the other for the "Final time". These two values identify an interval within the duration of the entire recording. This range is then automatically divided into consistent windows with the settings presented in the previous section.
The two fields in this section are therefore useful to set the values of the initial time and final time of the interval, expressed in seconds. The button located immediately next to the "Final time" field is only used to set the value of the final time equal to the duration of the entire record, which represents the maximum value that can be entered in this field .
Once the two values are set, the button "Select" starts the procedure for automatic selection.
When the procedure is concluded, the windows are identified in the table in the next section for further consideration .
Manual selection
In this section the are present tools useful to manually locate the windows to be included in the analysis.
The table collects information on the identified single window, indicating the temporal order of the window, its initial and final time.
When selecting a row of this table, in the graphics on the right side of the application is highlighted the related window.
The buttons immediately above the table have the following utility:
Add to diagram
Clicking on the button "Add to diagram" will start the procedure for the insertion of a window in the list of those that are already identified. After clicking on this button go to one of the three graphics of the traces. Clicking and holding clicked on one of these graphics, a window appears, with dimensions consistent with the indications in the general data section of the windows, whose initial time moves with the position of the mouse pointer. In this way it is possible to place the window in a precise point of the graphic of the trace (it can be noted that regardless of the graphic where is clicked, the window that moves with the mouse appears in the graphics of all three traces). When the mouse button is released the window is placed, and consistent with the data previously entered is shown a message asking to confirm the insertion in the event that is violated a condition previously imposed (eg. an overlapping greater than the one chosen in the general data section of the window). Once inserted the window, this is also inserted into the table, and then can be inspected and selected.
Add window
Clicking on the button "Add window" is opened a dialog box asking the user to enter the value of the initial time of the window to add. Once entered this information, clicking on the button "Add window", or pressing the "Enter" key on the keyboard, the new window is inserted in line to the data entered in the section of general data of the windows. If any previously imposed condition is not fulfilled, a dialog box appears asking to confirm the insertion of the window.
As soon as the window is inserted in the list of detected windows, this is shown on the graphic of the traces and inserted in the table to be inspected and selected.
Remove window
Clicking on the button "Remove window" it is possible to remove from the list of detected windows the currently selected window in the table below.
Filter
In this section are found the fields for entering parameters useful for the filtering technique of the windows, excluding those in which there are transients that have disturbed the recording. The specifications of the technique are given in the section of the techniques used by Easy HVSR of this guide. The fields in this section are:
Control window size
In this field is entered the value of the temporal dimension of the windows in which are further divided the windows identified with the techniques of the previous sections.
Upper and lower limit of admissibility
In these two fields are set the dimensionless values that identify the range of validity of the filtering technique.
Consider residual windows
If enabled, this option allows to consider in the filtering even windows that are smaller than the ones set. For more details see the relevant section of the techniques of Easy HVSR.
The filtering procedure is started by pressing the button "Filter".
The "Remove selection" button offers the possibility to eliminate in block all the windows identified until that moment.
The button "Apply" makes effective the changes made so far.
Graphical configuration
If windows have not yet been identified or if the selection has been removed, the graphics shown are only those of the traces as in the previous phase. In this configuration is however possible to proceed with a graphical selection of the first window to be included in the list of detected windows as specified in the description of the button "Add to diagram" of this help page.
If it has been identified at least one window, in addition to the three graphics of traces in the three directions, there are also present: a graphic for the average spectra, a map for stationarity of the spectra, a map for the directionality of the spectra. For the meaning of each graphic, see the section "Graphics" of this manual.
In this configuration, unlike that of the previous phase, if the windows have been identified, on the graphic of the traces are present rectangles that represent the time windows identified, within which fall the samples of the registration.
In the case in which the user selects a row within the table of the manual selection, the rectangle corresponding to the window relative to the row of the table is highlighted with a rectangle of a different color and a greater thickness.
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