!!!Worksheet 7 - Viewing the fit results

Since eis_auto_fit may fit many thousands of spectra for a single raster it is important to be able to quickly assess how accurate the fits were. The widget-based routine 'eis_fit_viewer' takes as inputs the fit structure and the original window data and allows the fits to be compared with the original data.

The calling procedure is:

IDL> eis_fit_viewer, wd, fit 

and a large graphic user interface (GUI) appears containing five graphics windows.

The top 3 graphic windows in the GUI show line intensity, line velocity and line width (FWHM). Underneath each window are text boxes that allow the image to be scaled using minimum and maximum values. The 'Auto' button automatically scales the images to preset values.

With the ‘Zoom’ button depressed, the mouse can be used to draw a ‘rubber-band’ box to zoom into the images. With the ‘Pixel’ button depressed, the line profile from the selected pixel will be drawn in the bottom-left graphic window. 

The bottom-right window shows a histogram of the selected image pixels for intensity, velocity, line width or chi^2.

Strange line fits will stand out in one or more of the intensity, velocity or line width maps through an anomalously high or low value. By clicking on such pixels one can see the original spectrum with the fit over-plotted. A bad fit may result from missing pixels in the data, line blending or simply be due to interesting physics going on.