Only spectra (i.e. dimension 1 data) can be plotted
as a spectrogram.
One example of spectra is the output of the fft operator when applied in the Calculator, (p0y = fft(q0)).
Only one spectrogram can be plotted in each panel. It is possible to plot time series at the top of a spectrogram.
The spectrogram is controlled from the Spectrogram Dialog.
When pressing the Grahics->Plot->Spectra in the igr menubar the Spectrogram Dialog appears.
When plotting data from a big time interval the user might use the Continuous utility in the ctm time manager. In this case the user must first select manual size of the spectrogram. See also Help in the Page Control Dialog.
The color of the spectrogram is selected from the
IgrColorSelect dialog. The IgrColorSelect dialog is shown
when Graphics->Panel->Color->Spectra is pressed.
The IgrColorSelect window is used to select colors for the spectrogram.
The left button is used to select number of colors. When the user press
this button, the Select Color Nr window appears. Here the user
can select number of colors for the spectrogram. Press Apply after the selection.
The second button from the left is used to inverse the color table. The button toggle between NRM and INV when pressed. The user can see the effect at once in the colorbar at the bottom of this window.
The third button from the left contains the selection of color table. When pressed the SelectTable window shows up. Here the user can select between different color scales. As before the selection changes at once the colorbar at the bottom of the IgrColorSelect window.
When the Done button is pressed the IgrColorSelect window disappears.
The postscript plot of the spectrogram is always in the selected color. The color selection in the Print Dialog has no effect on spectrogram.
It is possible to plot time series and spectrogram in the same panel. In this case the user must use the Panel Control Dialog and set the Scale to individual.
When the OK button is pressed the spectrogram is updated
and the Spectrogram Dialog disappears.
When the Update button is pressed the spectrogram is updated, and when
the Cancel button is pressed the Spectrogram Dialog
After the Ok (or Update) button is pressed the user must either press Update in the ctm time manager, or press the right mouse button in the panel containing the spectrogram.
|If we want to plot data that has unequal sampling intervals the spectrogram will not show correct time line. In this case a warning window appears. The user has then in the Spectrogram Dialog to set SizeX to manual and set a useful big number ( not bigger than the horizontal resolution of your screen ) in the the Spectrogram size, X (columns) input line.|
In the case when in the Page Control Dialog the use small ticks in the log. axis is selected, the major tick marks with labels are written on the color scale for each number being a multiply of 10. Between are the smaller tickmarks for all numbers being a multiply of 1. However when the tick marks are to many the smaller are automatically removed. The maximum number of tickmarks on the color scale before the small one are removed is 40 (INSPECT_MAX_COL_STICKS).