Displaying Fit and Residual Plots

In the Curve Fitter app, within each fit figure, you can display up to three plots simultaneously to examine the fit. Use the buttons in the Visualization section of the Curve Fitter tab to select the type of plot to display.

This example shows two plots: a plot with a curve fit and prediction bounds and a residuals plot.

When you select Prediction Bounds in the Visualization section of the Curve Fitter tab, two additional curves (or surfaces) are plotted to show the prediction bounds on both sides of your model fit.

Choose which bounds to display: None, 90%, 95%, 99%, or Custom. The Custom option opens the Set Prediction Bounds dialog box, where you can enter the required confidence level.

See also Customizing the Fit Display.

Viewing Surface Plots and Contour Plots

If you fit a surface, then the fit plot shows your surface fit. Click-and-drag rotation is the default mouse mode for surface plots in the Curve Fitter app. Rotate mode in the Curve Fitter app is the same as using the Rotate 3D button in the axes toolbar of MATLAB^® figures. You can change the mouse mode for manipulating plots just as for curve plots. See Using Zoom, Pan, Data Cursor, and Outlier Exclusion.

If you turn on a mouse mode for zoom, pan, data cursor, or exclude outliers, turn the mode off again to return to rotate mode. For example, click the Zoom in button on the axes toolbar a second time to clear it and return to rotate mode.

If you have a surface fit, use the contour plot to examine a contour map of your surface. Contour plots are not available for curve fits. On a surface fit, a contour plot makes it easier to see points that have the same height.

For polynomial and custom fits, you also can display prediction bounds. On the Curve Fitter tab, in the Visualization section, select a value from the Prediction Bounds list. When you display prediction bounds, two additional surfaces are plotted to show the prediction bounds on both sides of your model fit. The previous example shows prediction bounds. You can see three surfaces on the plot. The top and bottom surfaces show the prediction bounds at the specified confidence level on either side of your model fit surface.

You can also switch your surface plot to a 2-D plot. Your plot cursor must be in rotate mode. Clear any other mouse mode, if necessary. Then, right-click the plot to select Go to X-Y view, Go to X-Z view, Go to Y-Z view, or Rotate Options. All these context menu options are standard MATLAB 3-D plot tools. For more information, see Interactively Explore Plotted Data.

Using Zoom, Pan, Data Cursor, and Outlier Exclusion

You can change mouse mode for manipulating plots. Use the plot axes toolbar to switch to zoom in, zoom out, pan, data cursor, or exclude outliers modes. The Curve Fitter app remembers your selected mouse mode in each fit figure within a session.

Use the axes toolbar to toggle mouse mode in your plots:

Customizing the Fit Display

To customize your plot display, use the plot axes toolbar, the options in the Visualization section of the Curve Fitter tab, or the Document Actions button located to the far right of the fit figure tabs. See also Create Multiple Fits in Curve Fitter App.

Print to MATLAB Figures

In the Curve Fitter app, you can produce MATLAB figures from the results of curve fitting. On the Curve Fitter tab, in the Export section, click Export and select Export to Figure. The app creates a figure containing all plots for the current fit. You can then use the interactive plotting tools to edit and export the figures in different formats.