Plot Window

The Plot Window shows arrival times calculated for both forward and reversed profiles using parameters specified in the Model Window. Arrival times entered into the Data Window are also shown. Line fits are initially matched to the input model but can be edited to try to find a model that fits the observations.

Refract Plot Window

When the cursor is over one of the line fits, the apparent velocity and time intercept of the line is shown in the lower left corner. Clicking on a line segment will make handles appear at either end. The line can be moved by dragging on the line or reshaped by dragging one of the two handles. Once lines have been made to fit the data, the lines can be inverted for a velocity structure from the Model Window.

When arrivals from a layer are not the first arrival at any distance, the line from that layer extends to the plot edges; this indicates that such a layer would only produce secondary arrivals from that shot. Note that layers with a velocity lower than the layer above will never produce first arrivals; the lines shown for such layers are simply set to have the velocity of that layer and an intercept time equal to the two-way travel time to the layer top. Structures with low-velocity zones cannot be determined by manuevering the lines; such structures must be determined from forward modelling (i.e., adjusting parameters in the Model Window until data is fit)

You can hide (or show) any elements of the plot from the View menu, including the data points, model points, and the line fits.

The plot can be saved as a picture format file (like a .JPG) from the Save As... command in the File menu. (Windows users should note that deleting the file suffix may make the file difficult to use; first changing the file name and then selecting the file type from the popup menu should prevent this from being a problem). The graphic of the plot can be copied to the clipboard using the Copy command from the Edit menu.

The y-axis can be changed to a reduced travel time with the Preferences Window, as discussed on the reduced travel time page.