Fit Window

The Fit Window permits the user to find line fits on a time-squared vs. distance-squared plot in order to estimate the apparent velocity and two-way travel time of a picked times from a reflector. Once the Invert Picks button is pressed, line fits to all picked arrivals entered in the Data Window are shown as is a Fit Statistics button. The lines are identified with numbers corresponding to the reflector (one being the shallowest reflector). Statistics from the inversion are shown if the Fit Statistics button is pressed. Lines can be edited by clicking on them and dragging the whole line or the handles that will appear at either end once a line is selected. When the cursor is over a line, the two-way travel time (square root of the intercept) and RMS velocity of that line will be shown at the bottom of the window.

In general it is better to try and fit the points at smaller offsets to get a truer measure of the interval velocities.

Once lines are shown on this plot, you can invert these lines for a velocity structure by clicking the Model from Picks button in the Model Window.