iNMR icon

Plotting Many Spectra Together with the Overlay Manager

When an array of spectra is acquired as a single experiment, the spectrometer saves it as a matrix and you have, automatically, the same plotting options available for a 2-D spectrum. When, instead, the experiment is saved as a series of 1-D spectra, it's easy to combine them together with the Overlay Manager. This dialog can also be used to plot together two or more 2-D spectra (each one with a different color, possibly!).

How to Create a Stacked Plot with the Overlay Manager:

Step 1

Open and process all the spectra.

Step 2

Bring to the fore the first spectrum of the series.

Step 3

Choose Format > Overlay. The list of open windows appears (the foremost window is excluded).

Step 4

Select the spectra that you want to import as overlays: click into the boxes at at left of their names. To select all the windows at once, click “ALL”.

Step 5

Set the value (in screen points) for the progressive vertical offset between two spectra. With the initial value of zero the spectra are perfectly superimposed.

Step 6

Click Apply to see the effect. You can try with different values.

Step 7

If the order of the spectra is not correct, click Sort √ Spectra. This button sorts the overlays by name and by number.
If you desire a different order, click ALL to remove the overlays, re-check the names in the desired order, then click Apply to set the progressive vertical offset again.

Step 8

You can set the color for a single overlay: click the corresponding colored rectangle on the left. The gears icon extends the change to the other spectra listed above. An article on the web describes how to create a color gradient.

Step 9

If the frequency scale of the overlays is not correct, click Force Same Scale (copies the frequency reference from the foremost document into the other ones).

Step 10

Close the Overlay Manager. The first document stores the links to the overlays: in this way they can remain linked forever, unless you rename or delete the files (broken links are disposed of). If you move all the files together, the links remain valid.

In our example, it's not necessary to change the relative amplification of the overlays. If you use the Overlay Manager simply to compare different spectra, you can press the button Fit: the highest peak will become as tall as the window; or you can enter an explicit value for the amplification. When the dialog is closed, you can use the keys * and / to obtain the same effect.

If you double click a name into the table of the windows, the overlay is transformed into an exact replica of the corresponding document, including its frequency scale, integrals, window size, etc...

Related Topics

Creating a Poster

Subtracting a Spectrum from Another One

Keyboard Commands to Manipulate the Overlays

Tabulating the Integrals of a Series of Spectra

 

Web Tutorial

The Automatic Labelling Machine